I found some project that was up long ago, and it allowed you to send SMS messages to someone paying with Bitcoin. Project is now closed, but look like a fun idea. Would you guys be interested in such a service ? It wouldn't take me long to make this and code would be publicly available on GitHub. Let me know your opinions on this idea.
Edit:
Since some people are to bored to read whole thread, point of last project was not to send SMS cheaper than your carrier or whatever, point was to send it anonymously.