Hi,
We are in a similar situation and are succesfully using SVN as our source control. We also use
Tortoise SVN as the windows client and
Versions as the Mac client.
This works really well for us having set up users on SVN we can track the owner of the changes.
As for the file structure I tend to run a locallatest directory that then has the code in there. The organisation of the code is then in accordance with the project in question.
So, in a nutshell I have locally:
E:\locallatest\Code\ProjectName\src\.......
Then on the Server there is a C:\svn\repos directory that is the SVN repository.
Using the client like Tortoise makes setup and management really easy. You just need to update the passwd and auth files to add users to the system.
One final tip wold be to have each user follow the same structure for local files and have a policy of checking in all code each day AND only checking in compiled code.
I hope that helps.
nathj