Below you will find a few good links. Some of them will be interesting for novice users, while others provide in-depth information for professionals:
Wireless Ethernet LAN - General 802.11/802.11b FAQ
http://support.intel.com/support/network/wireless/sb/CS-008409.htm
Wi-Fi Planet Tutorials
http://www.wi-fiplanet.com/tutorials/
IEEE Wireless Standards Zone
http://standards.ieee.org/wireless/
WPA Wireless Security for Home Networks
http://www.microsoft.com/WindowsXP/expertzone/columns/bowman/03july28.asp
Configuring Windows XP IEEE 802.11b Wireless Networks for the Home and Small Business
http://www.microsoft.com/technet/prodtechnol/winxppro/maintain/wifisoho.mspx
SAFE: Wireless LAN Security in Depth
http://www.cisco.com/warp/public/cc/so/cuso/epso/sqfr/safwl_wp.pdf