A link to another interesting tool comes from Barry Bakin.
Wikisend allows you to upload files of up to 100MB. They will be available for 30 days from upload. You can access them yourself by emailing yourself the link. You can post the link somewhere, as I am going to do. I have uploaded the same Writing in Cyberspace presentation. You can access it for 30 days here. After that, the link won't work.
As Barry says, this would be perfect before a conference presentation: Upload your presentation to Wikisend and you will have access to it during the conference. If your bag is lost, if your computer crashes, whatever, you are covered. I like the idea.
By the way, you can keep a document live for anywhere from 1 to 90 days. And you can protect it with a password.
Thanks for the tip, Barry!