GHacks.net posted a tutorial about placing drives in the Windows 7 taskbar

Only specific programs can be pinned to the Windows 7 Taskbar by default, there is no option to pin files, folders or drives to it. We have already demonstrated how to pin files and folders to the windows 7 Taskbar, and today we are going to explain how to add drives to the taskbar as well.

  How To Place Drives In The Windows 7 Taskbar