My Documents Folder (and Desktop) - When you save on your desktop or in your documents folder, the files should be available to you whenever you log onto a networked computer in the school (Windows or Macintosh). They also count against your total quota. For hints on managing your quota, check the Manage your Storage Quota page. And I recommend Saving Early and Often!
Flash Drive - Flash drives (USB drives, thumb drives, 'geek-sticks,' etc.) continue to drop in price. Most any should work on both our Macs and Dells, and most likely on your computer at home (if you have one...) Some are sold as 2- or 4-packs in the 'big-box' stores. You might do a joint purchase with friends.
As of August, 2008, (opinions are those of Mr. Tryon)
Note on Flash Drives: some have extra software that provides security. This limits the cross-platform use of the drive. I would re-format the drive and get rid of the software.
gMail, mac accounts, and other servers -
There are various places on the net that allow you to store files for free or for a nominal fee. www.box.net is an example of one with positive reviews (see pcWorld for a review) Note that while it gives you 1 gig of space (a lot!) it limits any one file to 10 megs. (unless you wish to pay money).
There is a third-party add-on (for FireFox only) to open up your gMail account so that you can save in it. I have not used it.
e-mail to yourself -
Add an attachment to an e-mail to yourself. Note: apparently there is a permission problem with Hotmail and Internet Explorer. If you are trying to open an attachment from Hotmail at scool on a Dell, try Firefox.