To connect via WiFi, you need a WiFi enabled laptop or PDA running Windows 98 and above for PCs or OS 8.2 and above for Macs.
Most laptops and PDAs can be purchased from major equipment manufacturers such as Dell, HP, Toshiba, Apple, and others with WiFi preinstalled.
You can determine if WiFi is installed on your computer by checking with your retailer or manufacturer.
If your laptop is not WiFi enabled, you can simply enable your device using a WiFi card that simply plugs into your computer. Most WiFi cards cost less than $100.
Various WiFi card brands are available at both retail computer stores and online. You can also purchase WiFi cards directly from some manufacturers.
There are several hundred WiFi providers to choose from. Most of them have roaming agreements with each other that allow you access to a much larger base of WiFi hotspots. There are also WiFi hotspot aggregators such as Boingo Wireless, Airpath, and Trustive, which allow you to roam on multiple WiFi networks via one service provider.
Links:
www.beginnersguide.com
www.wifi411.com
www.uweb.uscb.edu