How can I get started building a bicycle?
My main resources for pretty much anything include:

Sheldon Brown
In particular:

sheldonbrown: how-to-fixed-conversion

sheldonbrown: fixed-conversion

Loads of general wrenching info at
Park Tool

And of course a friendly local bike shop. 

Look out for a bike co-op or skills-sharing non-profit/community organization. They may run classes and provide parts and tools.