I purchased GThing and have Vista 64-bit. I can confirm GThing does not work with Vista 64-bit. I believe one could get the software to work in 32-bit. Make sure you know before purchasing. I read the requirements and noted where it says Windows 2000 and newer. So I figured it had been tested on 64-bit. I asked Ryan via the Paypal system and direct emails for a refund but didnt even receive any kind of response, so buyer beware.
http://game-thing.com/gtmanual.php?page=Requirements
Its a small investment, but obviously for the time the requirements page needs updated, until either there is a software or driver update. The reason it will not work in 64-bit is not directly related to GThing. Its actually the driver. 64-bit Vista simply will not use the 32bit LG driver, therefore you cannot communicate with the phone in GThing.
I sure wish I would have gotten any kind of word from Ryan, but no support and no refund.