Setting up a server-based network drive on my Mac

I have a WD My Book World Edition set up with my Linksys router. With my Mac, I have set up Time Machine with this network drive. What I hope to be able to do is be able to remotely access this drive, so I can access this Time Machine without being in the local network. I figured out at this point that the best way to do this is to set up a server on my Mac, something which I have no knowledge of. How am I to do this?