The Peery Hotel in Salt Lake City offers free Wi-Fi everywhere in the hotel: SuiteSpeed built the network and offers guests that may not have a Wi-Fi card a bridging device that plugs into an Ethernet port. The service doesn't require any special configuration on the laptop. SuiteSpeed offers the hotel reports on the use of the network and can help a hotel with billing, authentication and a portal page.
Glenn has heard that some hotels in the budget category opted for HomePNA, a way of running networks over existing phone lines using unused higher frequencies, and then provide Ethernet-to-HomePNA bridges to guests.
I have stayed at a ComfortInn that uses HomePNA for Internet access, just as described here. I brought my own SMC access point to provide wireless access from anywhere in the room.