Is there a "breifcase" function on a mac Leopard machine?

I have 6 mac’s and exclusivly used my macbook “black” for word processing, but today got a MacBook Air and plan on using both laptops. I’m wandering if there is some way to set up my mac’s so that if I change one document on one laptop it will update on the ofer automaticaly. Basicaly I’m looking for the mac verson of Windows breifcase. I think i am the only person who ever used that, bit I loved it. Btw, if it helps I have a .mac account. I know a lot of thing can be done with that, I just don’t know how much.