I have copied this guide from Orange UK support site. This guide shows how to configure a Nokia S60 mobile handset to be used as a Bluetooth modem for your Mac OS X computer and use the GPRS connection for browsing Internet from your Mac.

Download the NokiaSeries60+FC1.sit file and unstuff to the following location: Hard Disk\Library\Modem Scripts.

Setting up the handset
On the handset, go to Menu–>Tools–>Settings–>Connection–>Packet data.
Highlight Packet data conn, Scroll to When needed and press OK.
Then select Access point. In the Access point field and enter orangeinternet (or whatever is your access point name)–>Press OK.
Press the hang-up button to return to the main screen.

Pairing the devices
Pairing with your Mac computer from the mobile should be fairly easy. Just go to Bluetooth under Menu and pair the Nokia device with your Mac computer.

On the computer, click the Apple icon.
Click System Preferences and click Bluetooth.
Click Devices.
Click Set Up New Device.
If Bluetooth Hardware is Off dialogue box appears and click Turn Bluetooth On.
Click Continue.
Click Mobile phone and click Continue.
Click the entry with the name of your handset and click Continue.
Click Continue.
On the handset enter the passkey as displayed on the screen of the PC and press OK.
Press Yes.
On the PC, ensure Access the Internet with your phone’s data connection is selected.
Ensure Use a direct, higher speed connection to reach your Internet Service Provider (GPRS, 1xRTT) is selected.
Click Continue.
a) In the Username field, enter user
b) In the Password field, enter pass
c) In the GPRS CID String field, enter orangeinternet

Note: Details for steps a, b and c should be available from your carrier

In the Modem Script field, select NokiaSeries60+FC1.
Ensure Show Bluetooth status in the menu bar is selected.
Ensure Show Modem status in the menu bar is selected.
Click Continue.
Click Quit.
Close the Bluetooth window.

Setting up the connection
On the PC, click the Apple icon.
Click System Preferences and then click Network.
In the Show drop down list select Bluetooth.
Click the PPP tab.
Click PPP Options.
Ensure all Advanced Options are unchecked.
Click OK.
Click the Bluetooth Modem tab.
Ensure Enable error correction and compression in modem is not selected.
Ensure Wait for dial tone before dialing is not selected.
Click Apply Now.
Close the Network window.

Making the connection
On the PC, click the modem icon in the menu bar.
Click Open Internet Connect.
Click Bluetooth.
Click Connect.
On your Nokia Mobile handset press Yes when prompted

You will now be connected to your mobile’s GPRS inetrnet service