See 802.11 for a complete overview of the 802.11x family of specifications.
Also see the "Wireless LAN Standards chart" in the Quick Reference section of Webopedia.
See also "How Wireless Networks Work" in the Did You Know... section of Webopedia.

802.11a: An Excellent Long Term Solution
Since the debut of 802.11a products in 2001, network managers have been struggling with whether to install 802.11b or 802.11a. Here's why you should strongly consider the use of 802.11a for your next wireless LAN deployment.

Minimizing WLAN Security Threats
Most wireless LANs do not invoke adequate security measures to guard against attacks. Learn what security threats exist for wireless LANs as the basis for deploying effective security measures.

Wi-Fi Planet
802.11 news, commentary and information.