Your can try setting up your computer for an Ad-Hoc wireless connection. This will create a peer-to-peer type connection and should share the PC side wired connection. Your Pc needs to have a wireless card or USB key however. You could also try what's called a "Software Access Point." This is a piece of software that essentially does the same thing for you.
This looks like the best solution for you...
http://reviews.cnet.com/routers/synet-windy31-usb-wireless/4505-3319_7-32909973.html