Building Secure Wireless Networks with 802.11 Best of the Net
Jahanzeb Khan and Anis Khwaja provide a wealth of knowledge to help any home user or system administrator implement and secure a wireless network.

Hack Proofing Your Wireless Network
Hack Proofing Your Wireless Network provides information on everything you need to know to secure and protect your wireless network. An excellent book and a valuable reference.

How Secure Is Your Wireless Network?
How Secure Is Your Wireless Network? (Safeguarding Your Wi-Fi LAN) from Lee Barken is a great book on the hot topic of wireless network security.

Maximum Wireless Security
Maximum Wireless Security is an excellent book that provides thorough coverage of not only wireless security but also the fundamentals of wireless hardware, wireless protocols and more. This is a comprehensive book on wireless networks and it includes a CD with excellent tools to help you out.