You’re on Facebook, check. You have friends, check. And now you want them all to know the cool thing you’re doing. Facebook doesn’t allow you to “select all” friends when sending an invite, but there are some creative ways around it to select them all with ease.
1. Go to your Fan Page, Event, Group or page and click “Invite People”.
2. Be patient while your friends load. It will come up without anyone selected.
4. All the invites will go out according to the queue Facebook sets up.
There are several ways to use GreaseMonkey with Firefox, but I am currently testing to find the best solution.