It's not really possible to compare them easily. Why? Well, film enlarged using traditional methods is a chemical process which yields very subtle results. It's easy to compare a negative scan, but this can vary technology wise from about 2MP to well over 50MP, depending on how closely resolved the scan was.
An 8MP camera can print a shot quite large, but what is acceptably large is entirely debateable. There is a load of crap talked on various websites about how big a 300dpi enlargement is going to be. The simple answer I would say is that a 20D compares very favourably with 35mm negative film when enlarged to sizes of easily A3. I've done this myself.
I am aware that plenty of people have printed A0 and other "poster" sizes with smaller MP cameras happily. I've also seen shots which are awful at web size.... The individual picture makes a big difference!
Rob