I have a laptop running Windows 7, with a WiFi and Ethernet connection, it is connected to my router by WiFi.

I also have a desktop running Windows XP that only has an Ethernet port.

I tried Googling several guides but could not figure out how to make this work.

How can I share my internet connection so I can connect the XP desktop by ethernet to the Windows 7 laptop and use it's WiFi connection to provide internet access to the XP desktop?

What do I have to do on both computers?