If you want to get right down to the nitty gritty (as a great man once said) regarding digital camera technology, you really need to check out Canon’s Technology Library. This microsite (although I hesitate to use the term “micro”) has a whole stack of information on everything Canon from DIGIC, to CMOS versus CCD, to EOS evolution (including comparisons between film and digital), you name it. Most of this information, while being obviously Canon-specific, is of general relevance to digital photography.
Canon Technology Library