It's not just a Verizon thing. It's AT&T too. I have had this for the past 2 or 3 weeks and I'm on AT&T. This is since I upgraded to the 4.3.3 software too. Had 3.1.3 and should have left it alone! My friends on Verizon are having the exact same issue. We all have iPhones - me the 3GS, them the 4. Different carriers, all same problem. We get more than 90% on the Sending bar, and then Message Failure, retry again. Very annoying. I called AT&T last night and as usual, they say they haven't had that problem in my area. Somehow I think it's just an overload on the servers or the towers. We've tried every trick in the book including resetting the network and getting a new Sim card. My husband has the Droid X from Verizon and does not have that issue nor does my daughter with her Blackberry on AT&T, and in same household. Is it an Apple issue then? Very frustrated at the moment.