The process is pretty straight forward. All you have to do is to log into Invite2Messenger site, then choose the service(facebook is only available at this time) from which you want to add your friends to your WLM list. Then the next step will prompt you to enter the email address which you use to sign-in at facebook. Once you have provided your email id, the service automatically fetches all the friends list from your facebook profile to which you can then send an invite to join you for a chat session on Windows Live Messenger.
Soon Invite2Messenger will also allow us to do the same for other services like hi5, tagged, bebo, linkedin and Windows Live Hotmail contacts.
From the official website:
With Windows Live Messenger, you get instant access to your friends through chat, voice, or video.
And if you join the i’m Initiative, you can do even more: steer donations to the social cause of your choice, every time you send a message.
The i’m Initiative works best when more people belong. The more people who use it, the more we can give. Asking friends to sign up gives the effort a huge boost.
If you’re already part of the i’m Initiative it’s easy to invite your friends from Hotmail or Facebook. Just sign in here with your Windows Live Messenger address, and we’ll get started.