A lot of people use gmail. A small part of those people are mac users with the macintosh address book application. And probabaly 95% of those users use Address Book with Apple Mail. The problem is that if you send an email through the internet based gmail but normally send them through Apple Mail, then, unless you have the address memorized, you'll need to get the address.

Why not just upload your email addresses from Address Book to gmail. Using AddressBookToCSV you can do just that. It will export your Address Book to a format read by the gmail internet application so that no matter where you are, you can have you addresses!

This tip was written by MacTipper, a great blog with loads of tips for Mac OS X. Check it out.