Microsoft

PDANet allows your laptop (or desktop) to go online wirelessly by connecting it to your Windows Mobile Phone through the sync cable, Bluetooth or even wifi. PdaNet goes through the unlimited data plan on your phone and does not require any extra service.

If you don't know what PDANet is, check it out here.

If you do, and have been looking for a 64-bit compatible version that works under Vista x64 and Windows 7 x64, go here.