Alexander Sandström Krantz has self-published a report, entitled “Practical WLAN Security”, that he put together along with David Johansson for a class at Linköpings University in Sweden. I just caught his post on SecurityFocus’s “basics” list, and have glanced over the text, and it looks to be a very well written introduction to 802.11 network security issues. This is definitely something you should pick up and read if you’re getting a start on this subject
http://wireless.sandstromkrantz.se/
Update: Mirror at http://www.cyd.liu.se/~alesa195/

I apologise that the server went offline yesterday, just a few hours after I posted my mail on the security focus list. The server should be up again some time today and I’ve also set up a mirror of the site on a server with higher availability.
The mirror is located at http://www.cyd.liu.se/~alesa195/.
Enjoy the report!
Thanks for the mirror! I’ve updated the post.