Clearing all the rumors, confusions, Facebook E-mail id is online now and it will be upgraded to all profiles very soon.
The Facebook e-mail is given on @Facebook.com NOT on fb.com The email address is made from your vanity url/username. You can change the username once.
Important thing to be noted is, there is no separate mail portal or login like other e-mail providers Gmail, Yahoo, MSN etc. The Facebook E-mail is merged with your messages only. If someone sends you a mail to your Facebook id, it will appear in messages.
The e-mail allows attachment like normal e-mail service. You can attach any type of file. I tried attaching PHP file, which is also ok too.
To activate your Facebook email you need to wait for the popup. The popup will come near messages in homepage (in left menu). Once your receive the popup upgrade and activate your account.
Though the Facebook e-mail is released for a few active Facebook people only. It will be propagated to all accounts gradually.
Update: Link for upgrade to E-mail is : http://www.facebook.com/?sk=messages&upgrade
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