The Windows Mobile Device Center (WMDC), ActiveSync’s replacement for Vista, is now officially out of beta. So, if you already have Vista running on your PC, make sure that you pull it down. It comes in both 32-bit and 64-bit versions and supports both Windows Mobile 2003 or Windows Mobile 5.0.
If the download does not appear Windows Update, you can also pull it down yourself at these locations: 32-bit version and 64-bit version.