for video chat, the ps2 eyetoy will work (you can find for about 15-20 bucks used at ebgames or 30 bucks for brand new). or you can wait until the eyetoy2 comes out this spring-summer (atleast those are the rumored dates).
for audio, bluetooth headsets will work or a ps2 usb headset. I'm not sure if regular USB PC headsets work.