One thing that’s made Google’s free Gmail online messaging service popular is its multiple gigabytes of storage space. There are several tools that let you use the more than 2GB of space as a virtual Internet drive, the most popular being GmailFS. If you’d prefer to use software that’s independent of your base operating system, try Gspace instead. It’s a Firefox extension that’s easy to install and use.

Source: Transfer files to your Gmail account with Gspace