Ok, I've searched for this problem, have seen it several times, but haven't come up with a solution.
My texts appear as "text message not sent" on every text that I send to this contact; I've never had any problems texting this person before. We are facebook friends and so his number appears twice in his contact, once the way I had originally entered it and again the way it appears on facebook with the +1. I've tried every which way and it just doesn't work. It's not on his end, he still gets texts from people. I tried installing handcents so that I could delete all failed messages and it didn't help. Now i'm stuck. This is a big problem. Don't want to reset my phone or anything, there has to be a fix for this right?
Any help would be much appreciated.