Subversion (http://subversion.apache.org/) is something you can try out. It has an easy Windows client such that can use it through the filesystem.
Problems with most version control software is the merging of XML files, as you are using OSB and SOA (which are just configurations through XML)
it could lead to some problems.
CVS is another option that could be useful: http://www.nongnu.org/cvs/.
Most IDE's have plug-ins for both.