Every time you sync your iPhone© with iTunes©, a backup file is generated and put in a folder on your computer.
On Windows, the folder is %APPDATA%\Apple Computer\MobileSync\Backup\[some id]\.
Vista: %APPDATA% = C:\Users\[your username]\AppData\Roaming
XP: %APPDATA% = C:\Documents and Settings\[your username]\Application Data\.
On a Mac, it is User>Library>Application Support>Mobile Sync>Backup>[some id]>.
Works with the new iOS 4!
The file you should look for is named 3d0d7e5fb2ce288813306e4d4636395e047a3d28.
Simply upload that file to this website and you're done! :)
Try the new iPhoneSMSExport.com desktop (offline) application (for Windows)!

After performing the payment with PayPal, the software will be sent to your email address instantly.
(if you don't receive the automated email please contact us at support@iphonesmsexport.com, it's because your mail provider may block that mail as spam).
Unlimited exports, no additional fee.
The backup file MUST NOT BE ENCODED (it is not the default setting, but make sure the checkbox in iTunes is unchecked).

Three Simple troubleshooting steps:
Disclaimer and privacy policy
This site is not affiliated with Apple Inc.
Uploaded files are automatically deleted by the system. No personal data is collected.
6588 files exported so far... :)