You can also simply click on Start>Programs>Accessories to find the item there listed as Windows Sidebar. To go one step further simply right click on that and select the "create shortcut" option to see a second item appear at the bottom of the dropdown menu there and simply drag that onto the desktop.
That will be seen as Windows Sidebar (2) which is easy to correct with another right click on that for properties and go into the General text window to backspace from the end to remove the (2) and press enter. It's as simple as 1-2-3 and you have ready access to bring up the sidebar any time you want it. A right click to close out.