I Need a Good, Free Version Control Software for Home/Office Business/?

[Brian]

I am looking for version control software that can be used over a network on multiple computers that can manage files including word documents, excel spreadsheets, and much more. This software needs to be user friendly and I'd prefer it if it was usable over internet explorer or FireFox. Our issue is a new office is opening up and as everyone is on the same wireless connection, our FTP program, ZFtp is not allowing us to connect correctly without hooking up using a Sprint card, this may be a configuration problem on our end but we still can't seem to find a solution for this. Please let me know what my options are as I can't seem to find any easily on Google.