Git – the fast version control system
Git is a free and open source, distributed version control system designed to handle everything from small to very large projects with speed and efficiency. It is very simple to set up so I strongly recommend its use even for personal projects. There is no project simple enough that could not benefit from the application of this tool. You can find information and downloads at http://git-scm.com/.
A version control system or VCS (also known as source code management or SCM) is an unavoidable element for development projects where more than one developer is involved and the best practice even if coding solo. Furthermore, even though it is possible to apply continuous integration with no VCS in place (as a VCS is not a requisite of CI), it is not a reasonable or recommended practice to avoid it.
Other and probably more traditional (see legacy), options exist in the VCS arena such as Subversion or CVS, which you are free to use if you feel more comfortable...
