What's the best way to test sending/receiving MMS messages with Android?

I'm writing an app that stores secret (encrypted+hidden using steg) information in MMS messages. Obviously I need a way to test this, in particular, sending and receiving MMS messages. I have one Android phone, a Nexus One. I know that MMS's cannot be sent between emulator instances, but other than using up loads of MMS credit, is there another way of testing out MMS sending/receiving without just spending loads of money?

How do I know if my MMS is working?

Check the Android phone's network connection if you can't send or receiving MMS messages. An active cellular data connection is required to use the MMS function. Open the phone's Settings and tap “Wireless and Network Settings.” Tap “Mobile Networks” to confirm it is enabled.

Twilio just announced MMS support, and their marketing page has a test box to receive an MMS, could be useful for testing: http://www.twilio.com/mms