iMacs Update Rumors?
LoopRumors claims to have specs for the upcoming iMac updates with up to 1GHz speeds as well as Firewire 800 and Bluetooth integration on all but the low end.
MacNews.net.tc also claimed similar iMac specs and prices in late December.
Information available to MacRumors includes the following: iMac updates with _slight_ speed bumps, Firewire 800, Airport Extreme-ready, ambient light screen-brightness sensor>.
All the above sources (including our own) are relatively new and have no history of accurate predictions... and should be considered accordingly.