Wireless security is a dynamic field of study. It is important to know where to obtain the latest information on wireless technologies as well as information on the latest attacks. At the time of this writing, there are many standards under development that may drastically change the wireless landscape within the next few years. In addition, the features provided in each operating system are being enhanced and expanded constantly, so it is important to know how those changes impact your deployment.
More links can be found at: http://www.dailywireless.org.
IEEE 802 Standards Online is at http://standards.ieee.org/getieee802/.
The Wireless Ethernet Compatibility Alliance is at http://www.wirelessethernet.org/.
Linux Netfilter documentation is at http://www.netfilter.org.
The HostAP driver for Linux is at http://hostap.epitest.fi.
The FreeBSD Handbook is at http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/index.html.
The bugtraq mailing list is a primary source for breaking news on software vulnerabilities. The vuln-dev mailing list occasionally has in-depth discussions on security problems with wireless networks. Both can be subscribed to at http://www.securityfocus.com.