If you are using Pocket Informant 1.02 or higher, the sync logging is disabled by default. You must first enable Sync Logging in the Settings tab and then reproduce the sync issue by synching in order to generate a log we can dissect to analyze the issue.
In order to diagnose the problem you are having, we will need to see your sync logs. As of version 1.04 there are two ways to get this sync log. Both ways are easy:
- Mail on the phone: Open Settings and choose "Help". Then select "Sync Log". Using iPhone OS 3.0's copy/paste you can copy/paste the log or portion of log into an email directly on the iPhone to send to us.

- Desktop File Download: Go to the Settings tab. Make sure you are in the same room as a desktop or laptop computer on WiFi. This will not work on a 3G/EDGE connection. It must be a WiFi network that is shared with your desktop. Then go to the Settings->Backup/Restore:

setting and turn on the web service.
On your desktop browse to the IP address displayed on the page on your phone. If you have a firewall on your desktop make sure it allows access to that port number. You may have to temporarily disable that firewall or give access to the port.
Then right click and save the "PI_Sync_Log_(some numbers).txt" and ZIP or Compress it and then provide it to support. Please do not use Word or RTF or HTML - those mess up the formatting.