Same as my SMS2IPD tool that migrates SMS from Windows Mobile to Blackberry, SMS Exporter uses MAPIDotNet library found on codeproject, written by rwt33. The export speed on Windows Mobile is fast, but the import speed is very slow. On my HTC Dream flashed to Android 2.1, it took almost 2 hours to import 3000 messages – the process became slower towards the end and the phone would go to standby mode during the process. After the painful import , the message application is still responsive despite the huge message database.
SMS Exporter also supports backing up SMS to XML, which is useful if you want to read your SMS on a computer, or migrate your SMS to other phones.