How do I teach my pit bull to sit?

Last week I found a young pit bull (about four months) in the alley behind my house. She was so emaciated you could count her ribs.. After feeding her hearty meals for a week she's looking much better, however, I have never had to train a dog from scratch before and am not sure how to go about it. I'm trying to re-home her as soon as possible (anyone interested in a dog?) <-lol, but in the mean time it would probably be smart to start working on some basic commands for her. She seems to have absolutely not kind of foundation at all, sit, stay, housebreaking, etc...... So ....what do I do now? haha, help me internet people!!! lol. Also, if you live in Northern California and ARE interested in adopting her, you can check her out a href="http://www.facebook.com/profile.php?id=100000382548924#!/pages/The-Phoebe-Foundation/211685262207740" rel="nofollow"http://www.facebook.com/profile.php?id=1…/a her name is Phoebe and she's very sweet.