One more time, surfing on the web, I've jst discover a very good source of information about "how to use Git" and how to integrate with web site github.com.

This site a http://gitcasts.com/ and some very good piece of video a proprosed to user, from 123'user to "Advanced G33K inside user".

http://blip.tv/file/4094595
video 1 - Git Setup and init


Have fun !