I just got through searching for ways to invite all my friend (well over 2000) to like my new fan page.

I ran into a few codes that don't work anymore but I just tried this and it works as of 11/12/2011 using Firefox 7.x

With the latest of facebook updates, the old code trick to send invitation to all friends does not work anymore. Moreover, you’ve installed the last Firefox, and you can’t use anymore the url address bar to input javascript commands.