Some GIT Tutorials
Git Magic - Maybe the main and most complete GIT tutorial, available in several formats
16 Tutoriais de GIT - in Portuguese and in English.
Linus Torvald on GIT:
This is a bit silly, because he spends most of the time telling how he doesn't like the other version control systems instead of clearly highlighting GIT's features. But Linus is Linus so here it is