Here’s a guide from My-Symbian forum on how to connect and browse the Internet from your Sony Ericsson P990i or M600i

Setting up Bluetooth on the desktop computer

1) Go to your Bluetooth software configuration and under Network Access and select “Allow other devices to access the Internet/LAN via this computer” - very important step

2
a) If your desktop computer is directly connected to the internet, go to the properties of your network adapter which has connection to the internet in Control Panel/Network Connections, go to the Advanced Tab and under Internet Connection Sharing select “Allow other network users to connect through this computer’s Internet connection”

b) If your desktop computer connects through a wireless router/access point,in the Control panel/Network Connections, select BOTH your LAN adapter and Bluetooth LAN adapter, right click and choose Bridge Connections. After a while, both the LAN and Bluetooth LAN adapters would appear as a ?Network Bridge?. Right click and go to the properties of the Network Bridge. Verify that you are given an IP address by the router and that the DNS/Gateway points to the router.
For example, ip of the bridge could be 192.168.0.5, subnet mask-255.255.255.0 and Gateway/DNS- 192.168.0.1 (IP of router)

Configuring the Sony Ericsson mobile device for the Bluetooth Connection

1) Go to Internet Accounts->New account->Bluetooth Internet (PAN)

2) In the new account, select TCPIP->IP configuration and select IPv4 from the drop down, set IP address in the IP address range of your computer network (example- 192.168.0.10). Gateway should point to your router (i.e.192.168.0.1) and Netmask the same as your computer’s subnet (255.255.255.0) and click save

3) Select TCPIP->IP DNS address and choose IPv4 from the drop down and set the primary address to your router/DNS server’s IP address (again 192.168.0.1) and click save

4) Set roles to Client - Access point and click save

5) Save the account and add it to your Internet group with priority 1

-In My Bluetooth Places, start “P990i/m600i m-Router Connectivity”.
(Sony Ericsson PC Suite starts up and detects phone if you have it installed)

-On the mobile device load Web, it should prompt you to choose your group. (Internet->Connect). Select the group that we created earlier.

8) On the PC you should get a Bluetooth Authorization Requested. Click OK.

Now you should be able to browse the internet from your Sony Ericsson phone using your PC bluetooth internet connection