It is rumored the 450D will be announced January 24th, 2008. That would be a week before PMA begins.
Proc: DIGIC III
LCD: 3″ Not VGA
AF: 9 Points (4 new cross sensors around center point)
Special: Live View
Special: Movie Mode
Special: Face Detection
Special: Same menu system as 40D
Special: Wireless master built in
Special: Increased noise and DR performance.
Price: $599 (?)
Kit Lens: EF-S 18-55 IS
The 40D was priced very aggressively, I expect the same from the 450D.