Kante,
If a developer requires access to only 1 folder within the web architecture, I would use FTP.
If a developer needs access to varied files, but not the entire thing, and the site is LOCAL (not over the internet), I would use Samba.
If you want to collaborate with multiple developers, setup a version control system such as Git or subversion.
The major advantage to Git or Subversion is you can give certain users access to check out, but not commit (save to the server), thus they would have to pass the completed code to a senior developer for integration.
What operating system they use is really not overly important as they all pretty well can do the same things from the standpoint of transferring files/code.
