Just a quick link to the BBC Tess site where you’ll find some good overviews of the characters.
This is the Wikipedia page for the novel, and is a good repository of information for our purposes. Brief and easy to understand, and well worth half an hour of your time.
Finally, this is the Spark Notes site for the novel, where you’ll stumble over all sorts of interesting and pertinent information. For those of you at the absolute cutting-edge, there’s a downloadable eBook, which is supported by most smart-phones. The website is free, the eBook is not.