Up until today, using MMS and firstname.lastname@example.org, I wasn't able to send pics to Verizon customers. The error message I was receiving was SMTP refused the connection. Doing a quick Google search on this, I've found that several others are getting the error message too. It looks like the culprit is the Yahoo mail account on the iPhone. By switching the default mail account in Settings>Mail I'm now able to send pics to VZ handsets using POP mail on a domain that I own. I just set up a little dummy account email@example.com to send pics with. To bad it's not PUSH.