Portable Networking system?

At home I have a laptop and a desktop PC, and they're on a wireless network, as is so often the case. Unfortunately, I don't have the time to go through hell to set up filesharing properly.

I need something that can run off my USB drive (it's ok if it isn't portable, I'll just make a BAT registry wrapper) that will automagically configure my laptop and my desktop to connect to each other and to share a specific folder of my choosing (e.g., C:\Documents and Settings\Owner\Desktop\Share) on the home network, without opening security holes.

Any thoughts?

~nm35 {blog}