Need help with Backup Strategy!

Hi all,

I'm the only tech at a non-profit, and I'm relatively new to the network administration world. We currently have 1 server which houses everything - Exchange, SQL, AD, user data, and network applications. We also have an older server which isn't being put to much use.

We backup the network data each night to tape, but we would like to have the entire system backed up for redundancy.

We would like to set up a live mirror on the unused server which would be used as a backup server, so if there's a hardware failure we could just kick over to the second server in minutes.

Is this possible? Do I need to match the hardware on both servers so that the OS device drivers are the same, or does that not matter?

Also if anyone has any mirroring software they could reccommend that would be excellent.