I haven't had the problem since the 2.3 update was released. It used to happen 2-3 times a day with me... I sent some interesting stuff to my grandma that I was trying to send to some Craigslist douche. After that I had to delete messages from certain people to be sure that they didn't send to teh wrong person (because who wants to send craigslist stuff to their grandma, or drunk texts to their mom?). I tried Handcent, but it sucked too much. If you don't have 2.3 get it and it should fix it.