I got an IBM for £150 (1.4 kg, 20GB, 128 ram) fromhttp://www.sterlingxs.co.uk/scpages/...hedlaptops.htm
A friend got a Compaq of a similar weight - but better specs, and a bit more expensive- from the same people. No complaints at all. Machines were in great condition and packaged with customised recovery cds- windows 98 se in my case (ugh) and 2000 for my friend.
I realise it's probably not much use if you're based in the states, but they're a great company. I'd buy from them again.