Haven’t finished working through them, but these git intros feel pretty useful. Slideshare alert if you’re allergic.
Introduction to git is by the venerable Randal Schwartz. Got a little dust. If up to typical Schwartz standards, still well worth reading.
Lemi Orhan Ergin’s Git branching Model might be overly stylish, but looks like it goes into detail on merging in addition to branching.
Via Rajiv Pant.