eBay and Craigslist finds

i'm sure you could already tell this but i'm not the most informed person in the world re: bike modification
why are track frames preferable to road frames on a fixie? it seems like they'd be a huge gap where the cassette is if it was fixed

As far as internet guides go, this one is pretty good

http://www.63xc.com/gregg/101_1.htm

and of course Sheldon Brown

http://www.sheldonbrown.com/fixed.html

http://www.sheldonbrown.com/fixed-conversion.html