I just received a new Motorola Droid yesterday, and then spent six hours trying to get it to sync with my Exchange Server. I am running SBS 2003.
At first, I was using a self-signed certificate. This worked with my Windows Mobile phones in the past, as long as I installed the certificate on the phone. I read in several forums where the Droid will not work without a third-party-signed certificate. Also, from my experience and from the forums, the Droid can not install certificates, even though it has a feature that appears to allow it.
So I bought a signed certificate from Go Daddy. Unfortunately, this did not change anything. I still could not sync.
I found this manual for setting up a Droid to sync with Exchange:
I followed the steps, but no luck. I had already done everything it described. However, at the end was a link to an Exchange Server troubleshooting guide:
I followed the steps listed under "Exchange 2003 SP2 Instructions," but my properties window was missing the button for "Device Security...." Now what?
After some more forum surfing, I finally found the answer. SBS 2003 did not automatically install Exchange Server SP2. It had its own, scaled-down service pack. I then read where you could install SP2 on an SBS system. I did that this morning, and after my server rebooted, I was finally able to sync my phone.
This may not be the cause of your problem, but I hope some of the links above will help you or someone else.