With the email to SMS solution, there's two things to keep in mind.

1. You have to figure out who the carrier is and then figure out what their email address scheme is. Not impossible, but can be challenging in the case of multiple nations.
2. There can be a significant delay between the time the email is sent and when the SMS message is delivered to the recipient. One time while testing this with my phone, some messages were almost instantaneous and others took several hours.

I'm not discouraging it, but just wanted to point out some gotchas that I remember hitting the last time I looked into this for notification. (I ended up going a different route for the notification in my case.)