I finally figured out how to access the internet from my PowerBook connecting through my Motorola v600 and Bluetooth. Below are instructions for getting online with the Motorola v600 and ATTs wireless service.
Tested with the following setup:
-PowerBook G4 Aluminum (1.25) with Bluetooth
-Mac OS X 10.3.5
-ATT Wireless Service
1. Download the Motorola GPRS Modem scripts from here.
2. Unzip the scripts, and copy the "Motorola GPRS CID1" script file to the "/Library/Modem Scripts" folder.
3. Set up Bluetooth. System Preferences > Bluetooth. Make sure that "Show Bluetooth status in the menu bar is checked".
4. Turn on your Motorola v600, and make sure that Bluetooth is on and discoverable (Connections > Bluetooth > Find Me).
5. On your Mac, in the Bluetooth settings (System Preferences > Bluetooth) select the Devices tab, and then press the "Setup new device" button. You can also select this item from the Bluetooth icon on your task bar.
6. Follow the instructions and pair the Motorola with your Mac.
7. In step 4 of 5 of the pairing process, make sure to check the "Access the Internet with your phone's data connection" checkbox, and select the "Use a direct, higher speed connection to reach your Internet Service Provider (GPRS, 1xRTT)" Radio Button. Select continue.
8. In the next screen, leave the username and password blank. For the GRPS CID String enter *99#, and for Modem Script, select "Motorola GPRS CID1". Click continue. Then click Quite.
9. Open Network Preferences (System Preferences > Network), highlight USB Bluetooth Modem Adaptor, and click configure.
10. Don't change TCP/IP settings. Switch to the PPP tab. Leave everything blank, except the Telephone Number which should be *99#.
11. Click the PPP Options button, and make sure that "Send PPP echo packets" is unchecked. This is very important. If you don't do this step, the connection will disconnect after a few seconds. Click OK.
12. Switch to the Bluetooth Tab, and make sure the correct Modem Script is selected, and everything is checked except for "Wait for dial tone before dialing".
13. Switch back to the PPP Tab and click the "Dial Now..." button. Set configuration to "Other" and leave everything blank. Press the "Connect" button. After a second or two a terminal window will come up, just hit the continue button.
14. You should now be connected. Open a browser and browse to a web page to make sure you are connected.
Post any corrections, or improvements in the comments section (I will keep the article updated).