As my SMS'ing has increased over the last little while I'm getting more and more annoyed with the message sent notification that shows up on after sending a text message on a Windows Mobile Smartphone. Yes, I know that it will actuall go away by itself if you leave it alone, but I'm a mover and shaker.  I gotta move along to another task and having that message pop up is just annoying.  So, without further ado, here's the registry hack you'll need to do in order to stop that message from showing.  This should work on pretty much any Windows Mobile Standard / Smartphone (non-touch screen) device. 

First thing is to fire up your favorite registry editor. Your phone doesn't have one installed, so you'll have to get one and install it first.  I recommend PHM - it's good and it's free. In your registry editor, go to HKLM \ Software \ Microsoft \ Inbox. Create a new key with the name of Settings. Then select that key and create a new String value (you should now be under the new key Settings, that you just created) and set the name as SMSNoSentMsg and the value as 1  Reboot your phone and that's it.