Mike,
Assuming that your ISP's TOS allows you to proceed, then you have two obstacles to overcome: The physical set-up and the software. Since you're an RF tech the physical should not prove too hard for you. Here are a couple of ideas for you:
http://forums.netstumbler.com/showth...&threadid=3406
http://forums.netstumbler.com/showth...&threadid=4876
DIY PoE:
http://www.nycwireless.net/articles/poe/
PoE kits:
http://www.demarctech.com/products/POE/poe-main.html
As to the software, you will need a portal of some type. Nocat
http://nocat.net allows for a redirect/info page/ signup, etc. It's for Linux, is open source and free. Other packages exist, ranging from to cheap to expensive. A couple of examples are MikroTik and DeMarcTech. Do to the fact that the software is in fact a router, 99% of the solutions are *nix based. Some, such as the DemarcTech unit are a combined hardware/softare unit. Take
hratch's advice, and read the captive portal thread.
http://forums.netstumbler.com/showth...threadid=5028.