Configure upto 4 names+email_address and 5 messages and send SMS's from the pebble.
Basically, the app sends an email to the specified email address & it shows up as a text at the destination.
e.g. for a friend on rogers network here in Canada, you need to enter their_cell_number@sms.rogers.com.
Only tested on iOS. I expect it works on Android too.
BTW, no need for any other app on the phone besides the standard mobile pebble app.
Lastly, still a bit quirky --> e.g. sometimes 2 msgs get sent out.