Yes, yes, boo hoo, oh woe is me, my Canon 40D arrived on the day the new Canon 50D was announced. If only I had waited, my photos would be so much better with the Canon 50D.
Yeah right. I’ve already stated before that the equipment behind the camera is the most important part of image making. Sure, the camera does matter, but DSLRs are getting to the stage PCs got to a few years ago. Upgrading doesn’t significantly change the game. I’ll upgrade again in maybe 3 years. No rush.
The Canon 50D looks sweet though. 15MP sensor, better ISO, better LCD. Nice upgrade. Roland has linked to a few of the sites previewing or discussing the Canon 50D. The Rob Galbraith page is probably the most readable, but the DPReview preview has a neat comparison table to compare the Canon 50D with the Canon 40D.
DIGIC 4 processor Canon’s next-generation, 14-bit DIGIC 4 processor see its debut in the 50D, and it offers both more functionality and about 30% faster processing speed than the DIGIC III processor in the 40D….
The two cameras’ dimensions, body style and control positions are also the same (though the 50D is fractionally lighter). In a nutshell, the 50D appears to be a 40D with a higher-resolution sensor, revamped image processing, faster CompactFlash write speeds, HDMI video out and a crisp new rear LCD.

Love this pic of the motherboard with the DIGIC 4 processor!