On 9 May 2011 I will be presenting the basics of Git to the Brighton Area Drupal Group. I am going to present a set of slides by Scott Chacon who has put together a selection of Git resources.
You will find some Git resources at my pinboard bookmarks. I would also like to recommend the Pragmatic Programmers books on GIT: Pragmatic Guide to Git; and Pragmatic Version Control Using Git
If time permits I will also take a look at DOG (Drupal On Git) which is an initiative to build a GIT workflow into drush.