There was a rumor that it was getting a very minor bump in November to the real Montevenia chips, but I didn't really buy it; however, given the 24" LED Cinema Display, the 24" iMac might get that screen in November. That would explain an update earlier than next year.
thanks zedsdead,
what is the advantage of 24" LED (i know in notebook it will save energy) but in desktop? all it will be expensive than 24" LCD, hey it will be cool though ...