This weekend I was at a hotel where the rooms had wired internet access and Wi-Fi was only available in the lobby. That wasn't great for the many devices, including the iPad, that couldn't connect over Ethernet. There's a new program that solves this problem, and it works with Windows 8 as well as Windows 7: Virtual Router Plus.
The program is similar to previously mentioned Connectify, but has a smaller footprint and is simpler to set up (just give your network a name and password), albeit with fewer settings options than Connectify or Connectify Pro.
If your hardware supports it, you could even share a wireless connection with other wireless devices.
You can download Virtual Router Plus here.