Here’s an interesting way of backing up yout text messages and conversations on your Device (current release only supports backup but according to the developer, next release will also feature the restore function).

According to the description, the application “reads your SMS account (no MMS available yet) and sends a backup of all your SMS Conversation (threaded) to an email account of your choice. The body of the email is filled with your conversation (one email per conversation). You can also choose to send a backup of your SMS account an an attachment in a separate email for future restores (Restore option will be available in the next release). You can also choose to clear out your SMS account folders (Inbox, Sent, and Deleted)”. You need to download the CAB and install it either to your Device or to Storage Card.

(Source: XDA Developers)