Problems connecting to a public wireless network, like those at bookstores, coffee shops, or schools? PC World has a Wi-Fi Troubleshooting Guide (July 7, 2005) with possible solutions.
Other wi-fi resources:
Wi-Fi Alliance, “Windows tips and techniques for Wi-Fi networks”
Apple Computer, “AirPort and AirPort Extreme: Using public networks, or “hot spots” to access the Internet“