Software For Recovering Deleted SMS
A UK company has come up with a software to recover deleted SMS.
I visited their website, which says that the software, PhoneFile PRO, helps to recover SMS from the SIM card that have been marked as deleted. Whilst this might be able to recover a very recently deleted message, it possibly cannot recover older messages, simply because the SIM cards dont usually have that much capacity to store that many SMS (deleted or undeleted).
For more details, visit http://www.pipistrel.com/phonefile/1special.shtml.