Cloud Drive is a free desktop gadget for Windows 7 which allows you to easily drag and drop files to your Google Account. Once you install the gadget, login with your Google account and you can easily add files to Google Docs account from your desktop. The gadget creates a secure HTTPS connections to your Google account. There is also an API feature which allows you to view last uploaded files.
If you have a premier edition of Google docs, you can virtually add any type of file using this gadget.