SMS time stamps are behaving strangely
What timezone are you in? It sounds like when you back them up, it is saving them in a different Timezone (maybe UTC). 

to answer your other questions:


Yes, SQLite is used for the messages
/data/data/com.android.providers.telephony/databases/mmssms.db
Same way as SMS messages : /data/data/com.android.providers.telephony/databases/mmssms.db
You can use ADB from the android SDK and copy it to your PC by doing:
c:/android-sdk/tools/&gt; adb pull /data/data/com.android.providers.telephony/databases/mmssms.db c:/users/my-account/desktop/mmssms.db
Yes, you will have to root your phone to get access to that directory.


maybe check out SMS Backup + in the android market. It will backup your sms messages (doesn't do MMS yet) to your GMail account and put them in an SMS label. It will also restore them too.