Yahoo! India is offering a unique service wherein you can forward important SMS recieved on your mobile phone to Yahoo! server for secure online storage. The SMS will be stored in Yahoo! Mail and you can access them anytime through your Yahoo! Mail account at mail.yahoo.com.

This is a two step process:

Step 1
Register and follow simple instructions. You will be sent an activation code on the mobile number specified. Confirm your registration.

Step 2
Start using your Yahoo! India SMS Backup! Just forward the SMS you want to back up to 82438243

I am not sure if this is available for other Yahoo! country specific sites but is definitely a secure way to store SMS messages and you don’t have to worry about deleting or formatting your phone anytime.