There are tons of mailing lists and such out there for Wireless ISP's where you can learn a ton about wireless networks and how they work. Those are probably the best source of information out there. It's hard to build a wireless broadband resource site and expect to cover everything, so most of the info. you will find is going to be in mailing lists where questions can be answered as they come up.
A couple of resources off-hand:
ISP Planet's Fixed Wireless How-To
802.11 Planet
ISP-Wireless Mailing List (Check out the archives here, although it is VERY massive - thousands of messages go through here on a weekly basis)
Most of what you'll find is going to be commercial unfortunately...everything we had to learn we basically had to sit down with the actual equipment and learn it, although the mailing list above was always a great help to us. Though the commercial sites can have a lot of good information on how their products work, which can give you an idea of how things work in general.
It's a very interesting business, especially if you're into technology and it's still relatively "new" technology, yet has been around for a while. It's just now starting to become more widespread as private ISP's are beginning to get sick of regulations and the monopolization from local and national phone and cable providers. Using wireless, we never had to deal with those companies and could deploy a competitive service VERY cheap and much faster than they ever could.
:cool: