Hi Amanda,
Advantage is a horrible product and yes, it is of course tested on animals. ALL the commercial flea and tick preventatives are harmful.

First read about Advantage (from poster on Shirley's Wellness Cafe_:
"Mary Ann  lost her beloved bearded collie 'Kaimen' as a result of using Advantage Flea Drops. "Advantage flea drops were recommended by my veterinarian to control Kaimens flea problems. The drops were placed on the back of his head in the nape of the neck. After using Advantage for 13 months a growth the size of a golf ball emerged in that very same spot where the Advantage flea drop were placed.  The growth was made of a grey colored flesh with a putrid odor. A purulent putrid liquid oozed out of it. Kaimen was taking to the vet,  where I learned more about the growth and just how deadly Advantage is to our pets. The pesticide that is used in Advantage is called lmidacloprid and should NOT be absorbed through the skin. I learned that dogs and rats who were used to test this pesticide developed thyroid cancer and it affected their appetite. My dog Kaimen died at the age of two as a result of using Advantage which caused  a tumorous cancer to develop in his neck and which metastasized in his brain. I sent Bayer, the maker of Advantage, a letter with a return receipt but they never bothered to reply to my letter."

Here is some info you can read about the dangers of Flea and Tick products:
http://www.shirleys-wellness-cafe.com/avictim.htm#flea
http://www.shirleys-wellness-cafe.com/avictim.htm
http://www.shirleys-wellness-cafe.com/petallergies.htm

In asking what is safe for your pets....here's what to do...
-First take the steps to build up you pets overall immune system.
-Fleas and ticks look for "weak" host animals. The stronger the dog or cat's immune system is, as well as their better their general overall health, the less likely a flea or tick will choose them as the source for their next meal.
-To build up a pets immune system you need to feed it the best possible diet available. No commercial dog/cat foods...a Raw diet would be best.
-If the dog or cat was vaccinated as a puppy.....it's now done. No more vaccines....EVER! Over vaccinating your pet is one of the worst things you can do to it/for it. It will just cause absolute havoc on the immune system. You don't take vaccines yearly....nor should your pet. Vets that practice yearly vaccinations or 3 year vaccinations don't cure pets...they KILL them.

-To keep fleas and ticks away from your pets:
Feed them garlic a few times a week with their food. It's safe for them (dogs) and fleas and ticks don't like the animals that have garlic coming out of their pores.
-Use a spray of Neem, citronella, eucalyptus, mint, etc. You can buy the oils and make one your self or purchase a product like this: http://www.arknaturals.com/products/index.cfm?fuseaction=DisplayProductPage&Product_ID=11
My dogs are sprayed with this product every few days. I live in the South East US, and have a "herd' of rescue dogs.....none of my dogs have fleas or ticks...ever! I never use any commercial products such as Frontline or Advantage (and the other one's that are available).... None of my dogs take heart worm preventatives.....none have it, and the south east is heart worm central. A healthy pet will be able to deal with heart worm....it can kill an unhealthy one.  With my own pets....So far...so good.
Another thing that works to keep away fleas and ticks is to slice up some lemon peels and boil them in water. Let it cool and put it in a spray bottle. Spray down your dogs whenever you take them out. Fleas and ticks hate the scent of the lemon oil.

I hope this helps....

-dave

For more info on how I care for my pets....my Guru for petcare is:
www.drmarty.com

PS: as mentioned probably a 100 times by me here on vegweb....buy his book! Follow his advice and your dog or cat will thank you for it. ;)