64mb of memory is plenty for what you have in mind. If you want to go really small, there are a multitude of distributions available. Actually too many to list. Enter "small linux distributons" into your favorite internet search engine and you'll find more than you can imagine.

Also there are small versions that run off floppies and other live versions as well. So really the size of your hdd will dictate which way you go. P1's & 2's will do fine. I use a 500mhz box with 64mb for a firewall with IPCOP and Smoothwall. All they are, are stripped down versions of linux employing IPTables. And I might add that you can build your own from the kernel up. That's a fun project as well.

You can reduce the packages during install on most distros so you only spend about 200-400 mb on the hard drives. But don't expect lipstick and makeup. You'll only get the bare necessities.

But anywho, the resources are out there.

cheers