I just logged into my Gmail account and found that the "Invite Friends to Gmail" link at the top was gone. Instead, there's now a little box in the left sidebar to invite friends to Gmail. Type in an e-mail address and click the button, and they're invited, just like that. My 10 invitations were also increased to 50 - perhaps they're getting ready for a real release?
Rats, Brett beat me to it [webmasterworld.com]! ;)