To initiate a four way video chat in iChat AV for Tiger, you need a Dual 1 GHz G4 or any G5 Mac. (You can, however, participate in one with a single 1 GHz G4, dual 800 G4 or any G5 to participate). I'm sure there's a perfectly sound technical reason for the limits being so high, but ruling out Powerbook users from this seems a little, well, with want of a better word, crappy. If the new Powerbooks can cope with Core Image/Video, why can't they do iChat? Anyone else feel this is a bit disappointing? If I were to get an iSight to use with iChat, my friends and I wouldn't be able to do this multiple way thing as we all have the audacity to own Apple notebooks.