Are you using "Missing Sync"? If you are here are the setup instructions for that. I use it and it works GREAT!
Step 1: Choose Connection Type
Before you can use the Internet Sharing feature of The Missing Sync for Palm OS, you first must choose a connection type and configure your network settings.
A USB connection requires that you have a cradle or cable for your handheld that is connected to your computer.
For a Bluetooth wireless connection, both your handheld and your computer must be equipped with Bluetooth hardware. The two devices must be paired.
Step 2: Pair Your Handheld and Computer
In order to communicate between your handheld and computer using Bluetooth, you first need to pair your devices. Be sure that Bluetooth is enabled on both your handheld and computer before you start.
On your Mac, launch System Prefs and click on Bluetooth in the Hardware section.
Then click on the Set Up New Device button and follow the configuration Assistant.
Step 3: Verify your connection
On your Mac, launch The Missing Sync application.
Make sure the Bluetooth icon (the far right connection icon) in the toolbar is selected (in blue).
Step 4: Launch Prefs
On your handheld, go to the Application Launcher.
Tap the Prefs icon. This is usually located in the System category.
Step 5: Configure Connection
Tap on Connection.
Then tap on New.
Step 6: Edit Connection
Enter a name, for example “Mac Bluetooth.” Choose PC in the Connect to pick list. Select Bluetooth in the Via pick list.
Then tap the Tap to Find field next to Device to find your Mac. A list of computers in range will appear. Select the name of the Mac you'd like to connect with.
Tap OK, then tap OK or Done (depending on the device type).
Step 7: Configure Network
Tap on Network (or choose from menu on the upper right). Then tap New. Name the Service “Internet Sharing.”
Select Mac Bluetooth in the Connection pick list. Tap Connect. You will now be connected to the Internet via a Bluetooth wireless connection to your Mac.
Tap Done to exit the Preference panel. Now you can launch any Internet enabled applications installed on your handheld, like web browsers and email clients.