Steps -:
1.Download application from HERE
2.Install it in your cell.
3.After Installation open the app.
you will show option like -
(a) Backup
(b) Restore
4.Click on Backup...
wait for some sec while your messsges are copying in the sd card(memeory card)
5.If you delete your messages than dont worry your messages are safe in sd card(memory card)
open the app and click on Restore.
your messages goes in sd card(memeory card)
DOWNLOAD THE FILE FROM HERE -:
download link
SMS BACKUP APPLICATION