This one is HOT and was previously only available on *nix-based systems!!
GMail Drive is a free Shell Namespace Extension that creates a virtual filesystem around your Google GMail account, allowing you to use GMail as a storage medium with MS Windows.
Note that GMail Drive is still an experimental tool. There's still a number of limitations of the file-system (such as total filename size must be less than 40 characters), and it doesn't make full use of the secure internet protocols available.
Did I already mention that Alex still has some
free Gmail invites left?