What I've done before is hooked up a game console to a mini DV deck, recorded the video from the consoloe to the DV tape, then imported the DV into my iMac via FireWire. However, this solution is a bit pricy -- $1,000 for a decent Mini DV deck is a bit on the expensive side.
You could also try the Qcast tuner, that way you can use your PS2 to play media files that you have on your Mac hard drive. You also need the Sony Network Bridge, cables and a hub or AirPort station to make the connection.