I'm horrible at hills, which is not surprising considering my weight. I did an MS ride a couple of years ago (before I took a year off) and was actually going up a hill so slowly at one point that I thought I would fall over. If it makes you feel better, I saw some cyclists -- skinny dudes with a biking cap and everything -- walking up one of the very bad hills.

On the plus side, I don't even have to pedal on the downhill and I fly by people.