Where to start?
There's some good stuff here:
This site's FAQs are also a good source of info.
My suggestion would be to either start with a distro that includes ndiswrapper (an Open Source program that allows the Windows driver for Broadcom wireless cards to be used under Linux ... Linuxant is a commercial program that works similarly) or install one with a good package management system. Ubuntu, Fedora, or try a live CD like Knoppix which has excellent hardware detection.
Check for a Linux users group (LUG) in your area. Most are happy to help new folks get installed & running and they often hold install-fests for that express purpose. Find an IRC channel for your distro to lurk & learn.
Read a lot & be patient but persistent; you'll get there.