This is Dropbox. You want it. Here's the link. They have a little video there, right on the first page. It's worth watching-- it explains the whole thing. However, if you'd rather have ME explain it for you, read on.
Suppose you have a laptop and a desktop Mac. There is bound to be some item that you would like to have with you on both machines-- maybe it's a book you're working on, maybe it's a folder of website files for your 30th high school reunion, maybe it's a checklist of things you need to do when you go on a trip. In my case, it's all of those things. Problem is, it's practically unmanageable. If I put exact copies of the documents on my two machines, and then I use a document on Machine A, I have to remember to copy it back to Machine B. And I never remember.
This is a job for a computer. And good software. Enter Dropbox.
Dropbox keeps designated folders on my Macs in sync. If I add a document to one of those folders on one of my Macs I know it will show up on the other Mac in an instant. If I make a change in one of the synced documents Dropbox makes sure that those changes make it to my other Macs. I don't have to have all of my machines on at the same time to make this work-- if one is off, Dropbox will notice when I turn the machine on later and will sync things up right away after that.
Dropbox shows up like just another folder, and you can make as many folders as you want inside of it, and name them what you want to name them, just like any other folder, with the exception being that any item in the Dropbox folder will always-- ALWAYS-- be kept in synch on all of my Macs. And, believe it or not, on my iPhone too. (Click here for the iPhone app.)
Did I mention that Dropbox is free for the first 2 gigabytes? Did I mention that it keeps backups of the things you put in it? Did I mention that you can share files with PCs too? I should have. Anyhow, now I have.
I've shown Dropbox to a lot of Mac users and every single one has said "I want that!" Now they have it. And so can you. Go get it.
Check out my other posts-- there are more than 400. Need more help?
People on the mailing list go to the front of the line.