my Apple ID is …@mac.com — can I use it with iCloud?

Question

When .Mac first came out I signed up for trial and got "myname"@mac.com

I never did subscribe to .Mac or MobileMe, but it appears I still "own" that email address because I just logged into iCloud with with "myname"@mac.com as my Apple ID.

Is there a way for me to use/send/receive mail with that email address? When I try to set up iCloud/Mail with this email address it doesn't seem to take it.

Any ideas?