Just recently I've been using 2 additional messaging apps:
1) WhatsApp - so my friend (in another country, she has a blackberry with a limited messaging plan) & I can text each other without it costing her anything, and
2) Tablet Talk - it lets me use my Xoom tablet to send texts through either bluetooth or my wireless network as if they were from my phone. Of course my brother - the cheapest man on earth
- had to find a free app that does that too, after I paid $3 for Tablet Talk. He's using mysms
and apparently it allows you to send texts from either your tablet or your pc as if you were sending them from your phone. One thing Tablet Talk doesn't do is let me send or receive pictures on my tablet but that's not a big deal for me.
It's amazing the number of cool apps that are out there