After reading a good number of posts regarding Git as an SCM I had the chance to experience it and use it myself. With the help and guidance of Rein Henrichs, an extremely helpful member of the DataMapper (among others, I'm sure) project.
In working to create new features for DataMapper we are collaborating on a new conditions parser. To do our work, Rein has created an account on GitHub and branched from the existing Git repository for DataMapper. GitHub is a fantastic web application similar to other such web front-ends for SCM tools (such as Warehouse for Subversion). GitHub is currently in closed beta but, I would recommend signing up to join.
Back to Git itself. Like most SCM tools, it is a repository for whatever purpose you may see fit. However, unlike most SCM tools, Git is decentralized, the users are encouraged to branch and merge (with proper workflow), and it is being used by the largest and many, many small software projects, alike. Aside from DataMapper, other small projects include Merb, Mephisto, and the people at Viget Labs.
Rein is currently working on a presentation of Git, and its usage. I'm hoping he will post it up on his blog so that I, and anyone else may share in his extensive knowledge.