Multi SMS Sender (mass text sender) For Android
Review and how to of the Multi SMS Sender app.
So far I LOVE it. It is the best one I have seen thus far for Android! You can create groups and not only add and save numbers from your phone but you can also add numbers that are not in your contacts and it will save into the group you create. Genius!
I haven't had any issues with it yet and will come back and update after a couple months of use.