Those keyboard re-mapping programs are easier than digging through the registry settings that's for sure. Aside from this particular function you can do some very useful things like turning off Caps Lock. ;)
Back in the Windows 2000 days I used Scan Code Mapper for Windows [microsoft.com] to alter keyboard input. I'm not sure that still works with Vista though.
The Windows Server 2003 Resource Kit Tools [microsoft.com] has Remapkey.exe: Remap Windows Keyboard Layout
Beware: Windows 2003 tools aren't all tested to work on Vista or 7. I have read that Remapkey.exe does however work just fine with Vista.