Try Git from CodeSchool.com
Git Cheatsheet: There are lots of cheatsheets out there, but this one is a visual illustration of git structure and commands.
Git Immersion: a great in-depth tutorial with hands-on exercises.
Pro Git: a very thorough reference. If Git can do it, you'll find it here.
Atlassian's Git Tutorials: from the creator of (among other things) SourceTree, a free visual git tool for Mac & Windows.
Git Workflows: an overview of different ways that teams can use git.
Have fun with Git!
Upstream and origin may be difficult at first, but eventually it all makes sense!