I have searched these forums for quite some time and have had to piece together bits of information to see if it was possible to have my TG50 share my Internet connection with my PowerMac G4. It is possible and relatively easy! Here is the (hopefully) concise and accurate way to surf from your TG50 (or any Bluetooth enabled PDA for that matter).
First, you need to download these AppleScripts from: http://www.technohappymeal.com/archives/000070.html
At this site you will find extensive information regarding Bluetooth Internet sharing on the Mac. I recommend the read for those who are interested. Double click on the appropriate script. I set my script to launch at start-up as the AppleScript needs to run after a logout or reboot.
Secondly, you will need to configure the Clie TG50 as follows:
1. In Preferences, under Network, create a new service and name it something like Bluetooth PPP. Do not provide a user name and leave the password settings at "-Prompt-". Set the connection to Bluetooth.
2. Then click on "Details...". The connection type should be "PPP". Set the idle timeout to "Never". Uncheck "Query DNS". Next you have to provide your "Primary DNS:" and "Secondary DNS:" fields with the information from the "Network" preference pane in "System Preferences" on your Mac. Open "Network". Under the "Show" drop-down menu, choose the connection to be shared. Choose the "TCP/IP" tab and copy the information from the "DNS Servers:" area of information to the "Primary DNS:" and "Secondary DNS:" fields on your TG50. Make sure your "IP Address:" is set to "Automatic".
3. Lastly, click on "Script..." in the bottom right of the "Details..." screen. Click on the first drop-down menu item in this window and choose "End:".
This last bit of information was the last thing I needed to make this all work. Hopefully, this will do the same for you. Questions? Post them here. I'll try to help as best as I can.