In last ten years, we've seen emergence of Distributed Version Control Systems (DVCS).
IMO, the noteworthy advantages of a Distributed Version Control System against a Centralized one are:
- each working copy can be regarded as a backup
- the most operations can be done offline
- common operations are thus very fast because there is no network overhead
- new kind of very powerful features
You can read more with this illustrated introduction.
Today, the most used DVCS seems to be Git, Mercurial and Bazaar (like SVN which seems to be the mainly used Centralized one).
There are lots arguments for or against a particular system; for instance there, there, or there.
Each one will use the one matching the most his needs.
I've chosen Git because it matches my free and open-source philosophy, it is very incredibly fast and efficient, documentation and samples are complete and of great quality and Git's team is hightly reactive.
IMO, to 'begin' the necessary links are:
- User guide
- Git reference
- the Pro Git Book which is a very complete documentation to deepen the knowledge of the system