Find a nice 1-2 year old Dell on eBay. It'll be plenty fast for remote programming, and most other common tasks. Might still be under warranty, even. Just be sure to buy from a reputable seller.

I got a Latitude CPi-A PII/400 for $360 a few months ago, with CD, floppy, two batteries, docking station and PCCARD modem. Couldn't be happier, and I didn't blow $1000 on the rapid value errosion that comes with a new PC. One caveat: if you run on battery a lot, you can expect to have to buy a new battery as the used one may not have much life left in it.