When you are sending multimedia message, it should have an option..
Send via:
Multimedia
Email
Fax
Or when your prompted to enter a phone number, it should have an 'email' option for a button..
Your email may get sent to spam folder.
your email adress will look something like this
[email protected] (or something like that)
^^^^^^^^
Your phone number goes here.
Messages are charged over standard rate, not sure how much, check with your operator. I've also realised that AOL don't accept emails from phone numbers, so use hotmail or something similar.
hope that's helped.
-Adam