I have a Palm Zire 72 and a new Blackberry 8100 ('pearl') user.

Here's the steps I took to migrate data from the Palm Desktop software. The palm desktop software version is 4.14.

Before proceeding BE AWARE that the conversion process modifies each record in the palm database!
Each of your calendar and contact entries will have a new entry in the top of the 'note' section
The steps below insure that if you have a problem you can go back to the original Palm desktop data.

STEPS

Backup your Palm device to your Palm Desktop. Disconnect the Palm from your PC. Close the Palm desktop software.

Make a backup of your palm data (tips for doing so are on palm's website).

Connect your blackberry to the PC via the USB cable.

Install your Blackberry desktop software. Verify it connects successfully with your Blackberry.

Launch the Blackberry desktop software.

Click the 'switch device manager' icon. Follow the steps. Be patient; converting ~1000 appointments required over 15 minutes (lots of hard drive activity).

After sync completes start the Palm desktop software. If you go into each of your calendar and contact entries you'll see a new entry in the top of the 'note' section. This is a tracking ID that helps Palm re-sync these entries going forward.

FWIW I did not care for the way the Palm records were modified via sync. I installed Microsoft Outlook 2003, synced my palm to Outlook, then synced the Pearl to Outlook. I am selling the Zire and like the way Outlook prints daily calender and appointments on a sheet.