What websites are there where I could learn sign language?

The most convenient site is (http://lifeprint.com/). It will teach you how to use your hands to do it with description or explanation as to how to do it. Although you asked for one but let me give you additional one(http://images.google.com/images?q)
When you visit the site, each picture has a special site you can learn more about it.
But you can also learn a lot more from the following;
1 http://www.handspeak.com
2 http://www.commtechlab.msu.edu/sites/aslwed/browser.htm
3 http://www.mastertech-home.com/ASDLDict.html
4 http://www.en.wikipedia.org/wiki/sign_language
5 http://www.funbrain.com/signs/
6 www. aslbrowser.commtechlab.msu.edu/
7 http://www.signslanguage.com
8 http://www.lessontutor.com/ASLgenhome.html