I thought I'd share my experience trying to setup the Magic TrackPad to work with Mac OSX and Windows 7 via BootCamp. It was not as straight forward as I would have liked. This assumes you already have all the software updates for Mac and Windows installed.
1) First off, if you paired the trackpad with OSX you must unpair (remove) it.
2) Boot into Windows and pair it with Windows first. You will have to restart.
3) Start up OSX. Remove the battery cap of the trackpad with a coin. This completely shuts it off.
4) Put the battery cap back in the trackpad and pair with OSX.
I honestly don't know why you need to pair with Windows first and why you have to remove the battery to restart the trackpad but it worked for me. If the trackpad is paired with OSX first, Windows will recognize it but won't install it. After the trackpad is paired with Windows, OSX won't find it until you take the batteries out and put them back in.
Btw, I have 2009 MBP 15" running OSX 10.6.4 and Windows 7 64-bit.
1) First off, if you paired the trackpad with OSX you must unpair (remove) it.
2) Boot into Windows and pair it with Windows first. You will have to restart.
3) Start up OSX. Remove the battery cap of the trackpad with a coin. This completely shuts it off.
4) Put the battery cap back in the trackpad and pair with OSX.
I honestly don't know why you need to pair with Windows first and why you have to remove the battery to restart the trackpad but it worked for me. If the trackpad is paired with OSX first, Windows will recognize it but won't install it. After the trackpad is paired with Windows, OSX won't find it until you take the batteries out and put them back in.
Btw, I have 2009 MBP 15" running OSX 10.6.4 and Windows 7 64-bit.