Start the Bluetooth service:
    litljay:/ # service bluetooth start
    Starting bluetooth:  hcid sdpd hidd hid2hci opd rfcomm pand dund     done
    litljay:/ #

Get your phone's MAC address and the channel number for your phone's DUN service:
    litljay:/ # sdptool search DUN
    Inquiring ...
    Searching for DUN on 00:16:DB:D5:9C:1C ...
    Service Name: Dial-up networking
    Service RecHandle: 0x10001
    Service Class ID List:
      "Dialup Networking" (0x00001103)
    Protocol Descriptor List:
      "L2CAP" (0x00000100)
      "RFCOMM" (0x00000003)
        Channel: 2
    Profile Descriptor List:
      "Dialup Networking" (0x00001103)
        Version: 0x0100
    litljay:/ #

So we know that my phone's MAC address is 00:16:DB:D5:9C:1C and that the DUN service is on channel 2 (flashing). We need to bind this to a serial port. Use a text editor to edit the file /etc/bluetooth/rfcomm.conf:

rfcomm0 {
    bind yes;
    device 00:16:DB:D5:9C:1C;
    channel    2;
    comment "Jason's Cell Phone";
}

We also need the file /etc/bluetooth/hcid.conf, which is probably fine by default if you already configured bluetooth in Yast:

options {
    autoinit yes;
    security user;
    pairing multi;
    passkey ";
}

device {
    name "DESKTOP";
    class 0xff0100;
    iscan enable;
    pscan enable;
    lm accept;
    lp rswitch,hold,sniff,park;
}

Restart the Bluetooth service to get it bound:
    litljay:/ # service bluetooth restart
    Shutting down bluetooth ( dund pand opd hidd sdp hcid)                    done
    Starting bluetooth:  hcid sdpd hidd hid2hci opd rfcomm pand dund     done
    litljay:/ #

Check to make sure it bound the phone correctly:
    litljay:/ # rfcomm
    rfcomm0: 00:16:DB:D5:9C:1C channel 2 clean
    litljay:/ #
If it isn't (usually after changing an existing rfcomm.conf) you may have to replug your bluetooth adapter or even reboot.

Alternately, if the bind fails you can bind it manually just this once, knowing that it should bind automatically on the next reboot:
    litljay:/ # rfcomm bind 0 00:16:DB:D5:9C:1C 2
    litljay:/ # rfcomm
    rfcomm0: 00:16:DB:D5:9C:1C channel 2 clean
    litljay:/ #

I'll assume you have already configured your computer to be using NetworkManager.  Click on the NetworkManager tray icon , then select "Dial-Up Connections" > "Configure Dial-Up Connections...":


Enter the root password when prompted:


Dismiss the warning about NetworkManager limiting the use of the modem.  You will only be using this modem for one connection, anyway:


On the "Modem Devices" tab, click the  button:



/dev/rfcomm0



Set the "Baud Rate" to "115200", "Init 1" to

ATZ

and "Init 2" to

AT+CGDCONT=1,"IP","gateway"

Click , then  and bullet "Custom Providers" on the "Select Internet Service Provider (ISP)" dialog. Then click :

In the "Provider Parameters" dialog, enter something memorable in the "Provider Name" box. The name of your wireless carrier works really well. Type in a phone number.  *99# and *99***1# are the most common ones. Both work on Cingular's WAP gateway.  Uncheck "Always Ask for Password" and Enter the user name and password. On Cingular connections these are supposedly "WAP@CINGULARGPRS.COM" ("ISP.CINGULARGPRS.COM" for the ISP gateway) and "CINGULAR1", but I have connected using just about anything for both; even leaving them blank! Click  to continue:


In the "Connection Parameters" dialog, uncheck "Dial on Demand", check "Modify DNS When Connected", "Automatically Retrieve DNS", "Stupid Mode", and "External Firewall Interface". 300 seconds is what most phones use for the idle time-out on their internal browsers, so this should be OK.  You can increase it if you want, then click  to move on:


This brings us back to the "Modem Connection Overview" dialog, where we can click  and tell it  when prompted to configure mail:



Then it's only 3 mouse clicks to connect:  Click on the NetworkManager tray applet, select "Dial-Up Connections" and the connection we just created is there: