I've found a combination that, at least so far, seems to make the wiimote actually usable as a controller under a WinXP installation.
First, hit this blog page
http://www.winko-erades.nl/index.php?option=com_content&view=article&id=9:connect-your-wiimote-to-windows-xp-using-the-microsoft-bluetooth-stack&catid=4:windows-xp&Itemid=3He describes how to connect up a wiimote under XP, and, at least for me, it seems to work just fine, with some caveats.
1) I'm using an IOGear bluetooth adapter that came with a widcomm driver stack. I tried the widcomm drivers, they suck. Instead, I uninstalled them completely, rebooted and plugged the adapter back in. After windows spent a few minutes running through it's "New device detected dance", it installed the MS Bluetooth stack. THEN I followed the above link instructions and had the wiimote paired first time out.
2) HOWEVER, if you do this, the wiimote is paired via "no passkey". What this appears to mean is that if the wiimote looses connection to the pc, or if you power it off (wiimote or pc), you'll have to go back through this process to reconnect the wiimote. Not good.
To correct that, I used Wiipair.exe that you can find here
http://www.instructables.com/id/Wireless-Bluetooth-Voltage-Meter-using-Wiimote-P/?ALLSTEPSIt's a little down the page and is funky to download (you download an HTML file and then open that to get the EXE, but whatever.
When you run the WiiPair, put the Wii in pairing mode (I did this by pressing the red button inside the battery compartment) and then clicking the EZPair button.
This appears to pair the wiimote, but it does so using a passkey (the address of the wiimote backwards or some such thing).
Once that's done, it'll spin for a while, authenticating the wiimote, but eventually it should pop open a wii data viewer (Called WiimoteMT example.exe), that will actually show you the data being received from the wiimote (button presses, etc, even IR info and accelerometer data).
Now then, at least for me, I could power off the wiimote, power it back up and run the WiiMoteMT Example app and it should show wiimote data (no pairing required).
So I then removed the batteries from the wiimote, shut the computer down, restarted, the put the batteries back in, and powered up the wiimote, then started the WiimoteMTExample app again, and viola, wiimote data. No pairing or funky steps required AT ALL.
I'll keep playing with it, but so far, this is making the wiimote finally look quite promising.