You can manage your SMS from your computer with Lazy Panda.

To use SMS Management function, you should connect your phone to your computer and run Lazy Panda. Click the Data button, then click on the SMS icon to enter the SMS Management interface.

You can check your messages from the left pane under SMS.

Select a message listed on the right pane, then the whole message will appear at the bottom of the interface. You can Call this contact, Reply or Resent message to the contact by clicking the appropriate button on the interface. Or click Delete to delete an individual message.

Click on the Reply button, a SMS Chat window will pop up, and you can see the conversation with this contact in the upper pane of the chat window. You can reply the message like any other IM.

 
Click on the Resend button, then there will pop up a SMS Chat window. Choose the contact(s) to whom you want to send a message from the contact column, type in the message you wish to send to your contact(s) and hit Send.

Want to add phone numbers to your Contact List? You just need to right-click on a phone number from the right column, and then click the 'Save as Contact' to pop up the Contact interface. Fill in the contact's information, then click Save.
 

Lazy Panda allows you to export your SMS to your computer as an XML file.

To back up SMS data, just click the Backup button. Then a window like below will appear. Choose a destination folder and put in the file name and save it. You can click Restore button and select the backup file to recover the SMS data.

You can also import SMS data from iPhone by selecting "Import from iPhone" option, but make sure you have connected your iPhone with your computer.