I hate to be all anti-climatic here, but I have been doing this for 6 years now and I still manage all of my projects with a legal pad and pen. I have 2-3 contractors that work for me on an as needed project basis. I coordinate with them by phone and email and occasionally drag one of them to a meeting with me. I suppose I could come up with a far more sophisticated system or software, but I subscribe to the "if it ain't broke why fix it" school of thought and found my legal pad and pen seem to do the job just fine.
I once read a book about billionaire entrepreneur Richard Branson. His empire includes airlines, cell phone providers, entertainment companies, and billions of dollars being moved around annually. I was shocked to discover the guy manages the whole thing on a legal pad! He said he doesn't use a lap top and found his pad of paper worked great. I figured if it worked for a billionaire it would probably work for my little enterprise :)