The only one i have found that has a trial is
There is a trial based app and also a paid full version.
The link online is http://www.windowsphone.com/en-US/apps/e16efc44-d1e0-4797-b2c0-05d6a2272695
Zappi only allows you to back up messages that you send from Zappi though. Are there any applications that you know of where I can directly take my sms messages from my phone and transfer them to my pc? I contacted HTC about this problem and the only thing that suggested was to forward messages individually to my google account via my google cell, which is annoying and time consuming lol. I want to be able to transfer messages in bulk. My old Samsung Behold did it and that wasn't even a smart phone. If you don't have the answer don't worry about it. Thanks for replying