It's against the TOS to export data using the API.
Ah, then ignore what I said before.
It's also worth noting that you can't get e-mail or any other contact info from the API.
What's interesting about this argument, is that facebook used to have a feature to export all your friends to vCards. I asked their VP of Product Marketing recently why they got rid of the feature, and he claimed it was to protect users from spam. "Facebook is all about edge cases, and we haven't had the time to focus on the problems that would cause", or something to that effect.
I think spam is the biggest reason, after the inherent difficult of developing client-side apps, that online social networks growing towards email were more successful than email growing towards social networks.
Whatever other reasons there are to think Facebook sucks I don't think this is one.