Delete Individual SMS Messages
If you had Jailbroken Firmware 1.1.4 or earlier, you may have used an app called WeTool, which had the ability to erase individual TXT messages without erasing the entire conversation. Well, now you can do the same thing on your computer without the need to Jailbreak. That's right, you don't need to Jailbreak for this hack!
This hack is not confirmed to be working on Firmware 3.0
- Download PhoneView. Open it and click on SMS.
- Highlight the message you want to delete and hit Delete on your keyboard
- Click Apply Changes. Be careful not to unplug or bump your iPhone during the process.