I have a school project where I have to make a program(java), therefore I need some way to keep track of the changes I make to the sources; I decided the best way to do this it to create a git repository on my box.net account. How is this done?
The best version control system I have tried is GIT together with GitHub.
If you are just a single developer that works on a project then SVN is okayish. However when you start collaborating with other developers or work on multiple computers, then a distributed version control system really shines.
A really good app for working with GIT is SourceTree (free).