Goto your Messages on your phone, Go into Options > Email Settings, in the drop down on Message Services select your email address, and then go down and see if you have Confirm Delivery set to yes. If so change it to no.
From within the RIM Messages app on the device, navigate to Email Settings within Options (from the app menu). Select the Message Service (if more than one is configured on your device) that is generating the delivery messages on your PC. Make sure that both Confirm Delivery and Confirm Read are set to No.
Nope sorry they are all set to no I just double checked.
Or delete all your email accounts on your berry with email setup - and then add them manually again? (had to do that several times, to really get the right service books...)
could be a setting in outlook telling to confirm delivery or receipt, you might want to check that on outlook...