General Pet Info Sites:
Animal Planet.com - The Cable Channel Comes Alive on the Web
A wealth of information about animals (about pets as well as wild animals). Find out what's on TV or forage through all kind of quizzes, games and fansites. A very comprehensive site that can sure waste a lot of your time (but that's a good thing in this case).
website: www.animal.discovery.com

AVMA - American Veterinary Medical Association
The American Veterinary Medical Association is a not-for-profit association representing veterinarians working in private and corporate practice, government, industry, academia, and uniformed services. This site contains lots of information concerning the health and welfare of pets and animals.
website: www.avma.org/default.asp

Dog & Cat News
Australian website for kids interested in pets. The site is fun more than newsy, there are lots of games and stories all based upon a TV show in Australia. Be warned though, the site uses a lot of flash and shockwave and therefore requires a lot of load time, if you are on a slower connection be prepared to wait.
website: http://www.abc.net.au/dogandcatnews/mainpage.html

MSNBC - Pet Health
MSNBC has a news page on their site dedicated to pet health and issues. It's a great place to go for offbeat pet news as well as current 'pet' events and health information.
website: http://www.msnbc.msn.com/id/4602461/

Pet Travel.com
Good site for finding the travel and immigration issues for people bringing their pets to a different country. Includes up to date quarantine information for animals in over 100 different countries as well as information about pet travel restrictions from specific airlines (and other forms of travel).
website: www.pettravel.com

Cat Info Sites:
About.com - Cats
If you already know about.com you know they have information on just about everything. This is a good source of informative articles and tips about cats. The expert Franny Syufy is a cat lover with over 45 years of cat ownership experience and has studied veterinary medicine in order to further her knowledge about the inner workings and health issues of cats.
website: www.cats.about.com

Cat Fancy Magazine
Large site with lots of information for cat lovers including several articles and a large forum community featuring several experts. Of course you can also subscribe to the magazine online if that's your fancy.
website: www.catfancy.com

Catster.com
Cute and fun website dedicated to the cat lover. Forums, featured cats, photos, classifieds and a page for cat adoptions as well. Sister site is www.dogster.com (not surprisingly).
website: www.catster.com

Dog Info Sites:
About.com - Dogs
If you already know about.com you know they have information on just about everything. This is a good source of informative articles and tips about dogs. The expert Krista Mifflin is a long-time dog fancier who studies rare breeds and has a soft spot for special needs pets. Krista has been raising and training dogs for seven years.
website: www.dogs.about.com

AKC.org - American Kennel Club
Large site with information about specific breeds as well as the club itself. You can find breeders, clubs and events on the site as well.
website: www.akc.org

The Daily Puppy
Not exactly an informative site in terms of news or health care tips but The Daily Puppy provides something that everyone needs, their daily intake of cuteness. The Daily Puppy presents a new puppy photo every day and if these pictures don't make you melt you must be made of stone.
website: www.dailypuppy.com

Dogster.com
Cute and fun website dedicated to the dog lover. Forums, featured dogs, photos, classifieds and a page for dog adoptions as well. Sister site is www.catster.com (see above).
website: www.dogster.com

Ferret Info Sites:
Ferret Central
The website is rather plain but the information is top of the line. Information for ferret owners to be as well as old pros. Medical and behavioral information and links to a lot of useful information. Pamela Greene is an authority on ferrets and this site is probably the most useful ferret site on the net.
website: www.ferretcentral.org

Guinea Pig Info Sites:
CavyPop.com
A wonderful resource for Guinea Pig owners and lovers. Brought to you by the same people that are responsible for Hamsterific which means you can count on reliable information for whatever questions you might have regarding your little Cavy. A great and friendly community for the active Guinea Pig owner.
website: www.cavypop.com

Guinea Lynx
Large and informative site about everything guinea pig. You can find information on medical and health issues, housing, basic care and even news updates in the world of guinea pigs. A forum is available for questions and just for chatting it up with fellow guinea pig fans.
website: www.guinealynx.info/index.html

Pig & Pot Belly Pig Info Sites:
The Duchess Fund
Charitable organization for raising awareness of pot bellied pig health and medical issues. Contains info and articles concerning the health Potbellied Pigs. There is also a searchable database of ailments and treatments.
website: www.duchessfund.org

NAPPA - North American Potbellied Pig Association
The oldest potbellied pig service organization in the world and probably the most comprehensive information site on the topic of potbellied pigs. Loads of information regarding care, nutrition and training potbellied pigs. Breeder and Shelter information are also available.
website: www.petpigs.com

PAPA - Pigs as Pets Association
Non profit website with articles about pigs as pets. Includes information about what to do when adopting as well as informative articles on medical and other issues. Also contains information on where to adopt or rescue a pig.
website: www.pigsaspets.org

Pot-Belly-Pigs.com
Nicely laid out and informative site. Contains a good amount of information on Pot Bellies including considerations to not adopt one for the would be pig owner. There is also an extensive number of links to be found to further educate yourself and breeders when you decide to adopt.
website: www.pot-belly-pigs.com

Rabbit / Bunny Info Sites:
Fuzzy Rabbit
Rabbit website that includes health and medical issues, photo galleries, articles as well as a member forum. The webmaster has owned and cared for rabbits for 18 years and is very educated about the needs and wants of a rabbit. Contains good information if you are considering adopting a rabbit for you or your child.
website: www.fuzzy-rabbit.com

HRS - House Rabbit Society
Large charitable organization headquartered in California with 30 chapters nationwide. The site offers much information and can be overwhelming on your first visit. Lots of info for first time rabbit owners on a variety of subjects regarding care and nutrition. Includes a directory for finding a veterinarian for your rabbit if you live in the United States.
website: www.rabbit.org

Rat and Mouse Info Sites:
Pet Rats Canada
Don't let the name fool you. This site has good information for any rat owner regardless of where they live! A good wealth of information and articles including how to build a playpen, travel carrier as well information on toys, nutrition an ongoing photo contest and more. There are also links to rat fan forums and other rat sites.
website: www.petratscanada.com

Rat Guide
Rat guide is intended as a basic 'rat encyclopedia' of sorts for rat owners. It has many informative articles and information on information such as health, medicine, nutrition and breeding.
website: www.ratguide.com

Rat Palace
Extensive rat website that includes health and medical issues, photo galleries, articles, rat friendly veterinarian list and more. There is also a busy member forum to ask questions and chat it up with other rat owners. There is also a small shop with a few rat related gifts.
website: www.ratpalace.com