Note that this does not import your friends' EMAIL ADDRESSES. Might be just be, but I find the pitch a little bit deceptive: to me, "Friends to Gmail" implies that you can subsequently email those friends.
I had the same (incorrect) assumption. Emails would definitely be more useful.
That said, via the Facebook API a user can give your app permission to access their own email, but they (thankfully) cannot give your app permission to access the emails of their friends. I'd guess that's why he wasn't able to include emails in the CSV.
You can do this via yahoo mail. It's the only service I've seen that exports email addresses. I signed up for a fake yahoo account a few months ago. Works perfectly and exports to .csv just like this app.
I made this yesterday because someone on a mailing list I'm on wanted to view his friends birthdays on his Google Calendar and merge in some other contact info.
I'm working on email addresses, but as others have noted, it's not in the API and would probably get this application banned...which wouldn't be the first time for me as many of you may know ;)