If you want Google Side bar Gadgets on your Windows 7/Vista/XP you only have to install Google free desktop. You can also keep your Google Gadgets on your sidebar, a vertical bar show up on your desktop which basically functions as a control panel for your sidebar gadgets. If you’d rather not have a sidebar on your desktop , you can minimize it into tiny deskbar, you can use to keep a small google search box right in your Windows taskbar to find google gadgets and add them in a 2 clicks.
There is also Linux version and Mac version available.