I would like to Pet Sit and House sit - but not clear about what I should charge. Is the rate listed normally per pet - or does it include all pets.
It depends on the sitter. Most sitters do charge per pet, and many discount the cost for multiple animals. When you set up your profile, you'll get to list a variety of rates, like rate for the first dog, rate for additional dogs, rate for puppies, holiday rate, etc. That's a good start toward determining what to charge for a house sitting scenario, though travel sitters often give custom quotes to clients depending on their exact needs, since they're frequently dealing with animals other than dogs, watering plants, collecting the mail, or other tasks that are going to require a different amount of effort and time and aren't covered under the rates you can list on your profile.
I'd look at the profiles of people in your area to see what others are charging for services, and then when you're starting out, list your rates a little bit lower than average to draw in clients. Once you get a few good reviews, then move your rates up.