Hi Melvin,
You might take a look at Perforce. It is a product that is very good. AT the time I tried it, Perforce provided a free demo of the product, but it was limited to a max of only two users. Otherwise the demo does not expire. Perforce runs on an amazing number of platforms and interoperates between platforms.
Below is a link to perforce:
http://www.perforce.com/I tried Perforce with my Visual Foxpro 7.0 project across a windows/linux TCP/IP network and was favorable impressed with the product. It has both a standard and a browser interface, so you can take your pick. Its a neat product.
LelandJ