Finally, there is now a Chrome extension called Facebook Invite All, so if you are using the Chrome browser you can pick that up and it will add the ability to invite all your friends – and there is a GreaseMonkey script for Firefox to Invite All Friends if you want to try that as well..
Oh, and by the way, if you found this helpful please tweet it or share it on Facebook to help others find it too. The more people who share it, the more people it helps!