Wirelessly posted (iPhone 4S: Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A405 Safari/7534.48.3)
Look for an app called Phone View for the Mac. You have to pay for it, but it will download all your texts and everything else's on your phone to the computer.