File sharing was never easy, especially for big files. I don't trust GMail, even when it says it allows attachment size of 20M. I often had my GMail frozen attaching just a 7M file, after some 20 minutes (which is way too much for just a 7M file!).
Enter DropBox. 20GB of free online storage. And a desktop interface which sticks to your Windows Explorer/Mac Finder/GNOME Nautilus seamlessly. I won't say this is a new solution, since we had GMail drive once, and many others kept popping up.
What makes DropBox special is ease of use with friendliness. And you can keep working while it synchronizes your files quietly in the background. You can also set maximum download/upload limits, so that your browsing experience remains okay.
Go ahead. Tour Dropbox. See the screencast. Download it. Link your computer and start sharing. And be thankful to me forever!