TortoiseSVN 1.10.1 (32-bit)
TortoiseSVN is a very easy to use revision control / version control / source control software for Windows. It is based on Subversion. TortoiseSVN provides a nice and easy user interface for Subversion.
It is developed under the GPL license. Which means that it's completely free, including the source code. But just in case you do not know too much about the GPL: you can use TortoiseSVN to develop commercial applications or just use it in your business without any restrictions.
Since this is not an integration for a specific IDE like Visual Studio, Eclipse or others, you can use it with the development tools that you like.
As a Subversion client, TortoiseSVN has all the features of Subversion, including:
Most current CVS features.
Directories, renames, and file metadata are versioned.
The commits are really atomic.
The branching and marking are cheap operations (in constant time).
Effective management of binary files.