This is so easy, I can’t believe it didn’t occur to me long before this… My carrier was all about telling me what my SMS "e-mail" address is, but they didn’t mention what my MMS address is. This matters because an SMS message is only 160 characters (minus the sender’s return address), but an MMS message is 1,000 characters, plus a 100-character subject, plus it’s what you can add files to (viz., a picture message). MMS is more like a short e-mail than an instant message, which is pretty handy.

So to figure out how to send an MMS to your phone via e-mail (or PHP, say), just send a picture message from your phone to your normal e-mail address — and there it is: The "reply-to" is your MMS address.

As I said, it’s not rocket science, and I’m not sure why my provider didn’t seem to want to give it up. Oh — and no, you do not have to attach an image or file in order to receive an MMS. At least with my carrier, it’s all about the part after "@" that matters.