This is a very simple procedure, but pay close attention.
First, here are the requirements to attempt this procedure.
- An Ethernet Cable,
- Wireless Connected Laptop
- Bridged Connection Eligibility
1. Get an Ethernet cable, they are commonly blue, or yellow.
2. Plug one end of the Ethernet cable into the back of your Xbox 360 console, and the other end of your Laptop.
3. Log onto your laptop, (assuming you're using Windows), and find the list of your wireless/wired connections.
4. You'll see something like, "Local Area Connection 2", and "Wireless Network Connection 3". Make sure you're already connected to the Wireless Network before continuing to the next step.
5. Highlight both the connections, and right click one of them. Click on, "Add a Bridge".
6. A process will start which will bridge the connections, enabling your laptop to work as a modem for your Xbox 360. This may take as long as anywhere between seconds, to minutes.
7. When it's done, do NOT remove the Ethernet cable, until your desire to disconnect from the internet on your Xbox 360.
Hope this helped, see ya' later. :)