hardware for backup

I have 2 macs that I would like to network together and have one central backup hard drive. I am looking at starting out with a 2Tb raid system. The Mac server is to expensive. Does anyone have any suggestions on what I should buy and how to set it up.

Thanks

backup over a network is quite simple

what versions of OS X are the machines using, and are you going to attach the drive to one of those macs

Have you got a wireless network?

I am using OS 10.5.6 on both macs.

I have heard about network hard drives using a Cat 6 cable and triple interface hard drives. This is where I do not know what to buy or what is the best thing for me.

I also heard about using Cat 6 on both macs then connected to a switch.

Yes i do have a wireless network, But I would like the speed of Cat 6 or firewire. I am transfering large photo files or video.

Thank you for your help