I got this book from www.trapezenetworks.com for free a while ago. It has alot of useful information on wireless networks. It may be a little biased, but it was free. You can download it at http://www.trapezenetworks.com/bookP...nterprises.pdf . You can also get a hardcopy for just shipping and handling at their homepage.
Sorry if this is a repeat, couldn't find it anywhere else.