Both your Wii and your PC need to be connected to a router that has an internet connection. If you have a wireless router, the Wii can connect to it without any additional hardware. Instructions are provided with the Wii.
Your Wii must have the internet channel enabled. This can be purchased from the Wii store.
From your PC go to Playon.tv and download & install software on to your computer.
From the Wii Internet Channel go to playon.tv. This will show you a screen with the name of your PC. Click on the computer icon (for example, Emma Desktop).
You should then see a screen of available online services that you can watch through your Wii. One of them will be Hulu. Click on it to access all of the content available on the Hulu web site.