Synergy!

Synergy allows one ring to rule them all. Err, wrong story isn't it...? Oh yes, now I remember, Synergy allows one keyboard and mouse rule all the monitors and their associated boxes, whether linux, windows, mac, etc., for free. Similar to a KVM switch but that in that you don't have multiple keyboards and mice to deal with. Unlike a KVM switch you are not limited to seeing only one monitor. And it's free, free, freeeee. (KVM switches cost hundreds and even thousands of dollars.) It also handles the clipboard, screen savers, etc.. Put the monitors on a wall next to each other and specify their positions relative to each other.
Then update the hostnames file c:\WINDOWS\system32\drivers\etc\hosts to include their names and internal IP addresses. For example the /etc/hosts file may contain for your internal network:
192.168.1.100 OneXP
192.168.1.101 TwoXP
If it does not be sure to add it. Then make sure your "computer name" located in XP at "Start->Settings->Control Panel->System->Computer Name" matches OneXP or TwoXP.

References

1. Synergy's Website

Topics to still cover...

1. Updating this to 6 monitors including Linux, BSD, and Mac.