From Fedora Project Wiki
This is not the Ambassadors Join Start Page, go there first!
At this point, you've spent some good time, probably around a week or so reading up on Fedora documentation, lurking in mailing lists and IRC. You're likely very excited and ready to get to work sharing the Fedora love.
Join the Ambassadors group in FAS
Visit the Ambassadors group in the Fedora Account System and apply.
This is a good idea once you are approved, but it's not required. The FAmA administrator will add you once you are approved.