Why not do a fully blown Facebook integration? Just have a site that lets you pick any of your friends from Facebook, it generates an address for you that you send coins to. Later when that person has downloaded and installed the client, they sign in to the same site and are able to provide an address of their own to receive the coins. That seems a bit simpler than adding import/export features and it'd be very easy to code up using the Facebook API/AppEngine.

This wouldn't help for people who aren't on Facebook of course, but for those who are it's probably an easier and more intuitive experience.