Responding to the mention of this program by several other bloggers, I tried Dropbox, and I have to say I am pleased with it. Up until now, my solution to working on documents on multiple computers was the thumb drive, and I expect that I will continue to use it. But it was very nice to have worked on a document at home last night, dragged it into the Dropbox folder on my home computer, and then come to the office today and see a little pop up message after I turned on my computer, saying that that file was in my Dropbox folder on my work computer. How great is that?
I have not worked with it extensively, but my initial impression is that Dropbox makes working on the same document on multiple computers much more convenient, as well as reducing the fear of deletion, overwriting the wrong copy, multiple copies, and so on.