There are other methods of doing this, but Xmail Hard Drive (formerly Gmail Hard Drive, now relaunched with new name due to trademark issues with the term Gmail) is a web-based service as opposed to a desktop client application as with Gmail Drive (and is thus also cross-platform). The service allows you to use the space in your Gmail account as free network storage -- upload and download files via their web-based interface. I've just been trying it out and, other than being forced to re-login at one random time, it seems to be working pretty well (it's still in beta, of course -- beta is the new black). If anyone else has experiences to report, please post up the comments.

[Via populicio.us]