I set up a Freesco box over the weekend. It makes less sense now that router/switch/firewall combos from the likes of Linksys sell for $50 than it did when they sold for $200, but if you're long on unused PCs and short on cash, it still works.

My old walkthrough no longer applies directly to the current version 33, but if you're reasonably technically competent it should get you on your way.

As far as what hardware to use, I had a Kingston 10 megabit (NE2000 clone) PCI card and a D-Link card based on a Realtek 8139 chipset. They worked fabulously. The 8139 is a workhorse; networking guru Donald Becker blasted it in print--it's the only chipset I think he's ever said anything bad about--but until you start routing between a 100-megabit network and a gigabit network you probably won't notice, especially if you're using a 200+ MHz machine as your router, which in these days of $30 Pentium II PCs, is likely.

All you need is a computer with 8 megs of RAM, two NICs, and a floppy drive. To make it easier on yourself, make sure it has PCI slots, use two PCI NICs, and and 16 megs of RAM or more. Since 32-meg sticks are useless to most people these days, they're cheap. I suspect that if you have a pile of unused hardware that you're looking to turn into a router, chances are decent you have a pile of network cards in that stash. Try a few different PCI cards. Life sometimes goes a bit easier if the two cards have different chipsets on them, but it's not usually necessary to mix it up.

Give yourself a time limit. Mess around with it for an hour. If you get frustrated after an hour, go out and buy a Linksys or a D-Link or a Netgear. If you don't have it working after an hour but you're fascinated and you're learning a lot, then keep plugging away at it. The knowledge you're gaining is worth more than 50 bucks.