Quote Originally Posted by MDHillSlug
One of the obvious things would be gearing; lower gearing to make hill climbing easier. It's been pointed out to me that changing out a cassette is pretty easy meaning you could have one with lower gearing for hills and another with higher gearing for flats and speed. From what I can see it's an easy, 5 minute task to do the switch (see link) I know some of the girls here have done it.
A second possibility is that you probably wouldn't want a bike with a longer wheel base; those are mostly designed for comfort on the flats.
As I was midway up a hill on my ride this morning, and thinking how nice it is to have granny gears, I smacked my head and uttered a big "duh-uh." Of course that's it--gearing! If you're going to be climbing major hills, you want to think seriously about your gearing. As MDHillSlug pointed out, the gearing on most bikes can be changed, though it's not something I've done myself. You should definitely (1) learn a little bit about gearing, and (2) talk to the bike salesperson about getting the right gearing for you. (But first educate yourself so you won't be steered wrong by someone just trying to unload a particular bike.)

I'm not sure about the longer wheelbase issue. Touring bikes have longer wheelbases and they're generally meant for at least some climbing. You DO want a nice, light frame though, so you're not carrying any more ounces/lbs than necessary up those hills.