Which versioning system to learn on?
gexla: Github has emerged as such a great and widely used tool that I would learn Git just for that resource.  Besides Git, the next versioning system you will most likely see is Subversion.After learning Git, Subversion will look and feel very familiar because they share many of the same commands.  Subversion also has great GUI tools available.  So if you learn one, then the other will come easily.  You also don't need to get very far into the guts of either to be effective with working with a team.Working with a team on a workflow and versioning system is probably the next most important.  Probably the easiest way for you to do this without actually landing a paying Gig is to get involved in an open source project.That all assumes you are referring to a source control management system.  Versioning can mean many things.  ;)