I have had this for a couple of days now and it is spot on.
You need at least XP with service pack 2 to run the software, which can also be downloaded from Microsoft. Once you have this software running the PC will detect any Xbox 360 controller if the are the wired kind.
Once that is done just plug this in, press the scan button on top and press the scan button on the front of your wireless and a couple of seconds latter the lights on both units stop flashing and it's done.
The Xbox 360 controller is great with Gears of War, see my Gears review. I have it working on FEAR also, but you do have to set up the buttons on FEAR, I assume on other games also. Games like GEARS are written with the 360 controller already mapped out.
One final note.
They do not work through a USB hub. They have to be connected directly, same with the wired controller.
Great idea for the gamer. Buy it.