Link : 10 Xbox 360 tricks Microsoft won't tell you

I've tested Tip #6 and it works just great.Note that you'll have to use a cross cable to link up between your xbox and notebook. Good for me not having to shell out that extra $ for wifi adapter/wall ethernet adapters.

Have fun guys!

This is how I did it :
1. Select your "local area connection" and "wireless network connection", right-click and select "bridge connections"
2. Hook in your cross cable.
3. Renew your IP -
  - ipconfig /release
  - ipconfig /renew
4. Once your done with the bridging, select both connections again,right-click and select ... remove from bridge(something like that). and you're done.
I'm using a dell latitude d620 to test this.