Here you will find known issues and possible solutions when they are available to your use of a Pocket PC or Smartphone:

Unresolved ActiveSync Problems
ActiveSync Troubleshooting Guide on Pocket PC FAQ
Pocket PC Issues
Smartphone Issues
Windows Mobile Device Center FAQ

General Websites that offer support:

Pocket PC FAQ
Bev Howard's Pocket PC Tips, Tricks and Links
HPC Factor - Handheld PC Information

Links
Microsoft's Windows Mobile Homepage
OEMS and Carriers