Here's a quick tutorial on how to backup text messages (SMS) on your Windows Phone 7 device, thanks to a new homebrew application by shinichiwtn on XDA Developers, which utilizes native code to copy a backup file discovered by Thunder. You will need an interop-unlocked device, however, and are limited to first generation HTC and Samsung devices. This being said, if you fit those categories, this tutorial is very easy to complete (especially the first option).

What you need:

• An interop unlocked Samsung or HTC device
• The SMSBackup application
• An application deployer, such as the one in the SDK, the WPH Xap Deployer, etc

For manual/isolated storage: 

• Windows Phone SDK or the Mini SDK
• SMS Backup batch files

If you have any issues, let us know in the comments. Other than that, big thanks to the devs of this tool!