Use for iDisk?

So I have an iMac, and went and bought an 11.6 MBA that I want to keep synced with the iMac. Before purchasing a MobileMe account, would the following be possible?

1. Essentially move my iTunes Music Folder to iDisk (it's less than 20GB) and anytime I download a file, it automatically saves to that location.

2. Anytime that folder is updated, it is correspondingly updated on my MBA.

3. My iTunes plays all of the songs located on the iTunes folder, automatically moving them into the iTunes app, regardless if they have been played?

Or is there a better way to keep the two synced? I am on a school network, so doing anything too public is out of the question.