I recently installed CyanogenMod 7.1 onto my Samsung Captivate because I was getting sick of using the default ROM. One of the things that I noticed was SMS messages received while the phone was off or in flight mode had the timestamp of when they arrived to the phone as opposed to when they were sent. If you want to get the time that was sent, follow the directions below:
- Change the settings to use Sent timestamp
- Change the settings to use the GMT timestamp just to make sure all timestamps come in the same way
- Install SMS Time Fix
- Activate SMS Time Fix in the settings
- Set the adjustment time to be either add or subtract time zone depending where you are in relation to GMT
I hope this helps. As a note, if you're using CyanogenMod 7.1, the RC1 seems to more stable than the Stable version. I've had less force closes and no boot loops so far.