Way back in 2008, Microsoft wanted to add a feature to laptops that would allow them to become wireless access points when connected to Ethernet. The feature, which appeared on the Win7 roll-out list, is missing from the finished product but may be closer than we think.
By downloading Connectify, you can enable the Win7 feature and create a wireless connection. It’s in Beta right now so beware. However, it’s a cool little feature, especially if you need to share a single Ethernet cable with the whole office.