i don't know how accurate this is, but i just met a girl yesterday who used to work in georgetown admissions and she said that if you end up in the highly select pool, you still have great chances, but that you HAVE to write a letter of intent and kiss major butt to maximize your chances.
she also said, and this is a bit iffy, that though georgetown takes in a class size of ~170, 25 of those are from georgetown's grad program in physiology (almost guaranteed), and 10 are from georgetown's GEM (sp?) program for minorities. plus they like their own undergrads, so there are not as many open seats as might be expected.
don't quote me on it, though.