I do not subscribe to any data plans. I would like to have it so when I tap an email address in the address book, it defaults to Messenger and inserts the email address in the "to" field to send an SMS. Right now, when I tap the email address, it sends me to Eudora which of course won't work for me. Any thoughts on how to change this? Thank you in advance.

TakePhone can do this. You need to hit the message button, rather then OK though.

Alan