From what you are writing, I think you want to use your laptop's wireless connection (it would be helpful to know what kind of wireless internet you are using, BTW), and share that connection with the XboX to allow the XboX to be able to connect to the internet?
Is that correct?
If so, you will either need to enable the internet sharing software on the PC, or get a program like winproxy and install it on the PC to allow the XboX to be able to use the PC's internet connection.
This is something that is not easy to setup, and can open up your laptop to being exposed directly to the internet.
But anyways, please enlighten us on exactly what you are trying to do. Are you trying to connect the XboX to the internet? Are you trying to get files off the PC to the XboX?
As to connecting the xBoX directly to a laptop, many laptops have the ability to connect directly to another computer, and will reverse the transmit and receive pins. So in some cases, a seperate hub/switch is not needed.