I made these widgets with Randy Hoyt's wonderful RotateContent.com.
Here is the 200-pixel-wide version (good for blog sidebars):
And here is the 400-pixel-wide version:
There is also an iframe version that you can use in Canvas or similar environment that does not allow direct use of javascripts; you can adjust the height variable as needed; I have only created an iframe version of the 400-pixel-wide widget: