Fmail is new service from Facebook which offers Texts, chat and email together in one simple conversation.

Include email by activating your optional Facebook email address

Control who can send you messages through your privacy settings

No need for subject lines or other formalities

Easily leave large conversations that no longer interest you

Messages from unknown senders and bulk email go into the Other folder

Spam is hidden from view automatically

To get an Invitation

1. Login to your facebook account

2. Go to the Facebook Messages Invitation request page

3. Click "Request an Invitation"

You will have to wait for the invitation.

[Via The Copy Paste Blog]