If you notice on my profile, I have a Grazr widget at the bottom of the page. The code Grazer gave me wouldn't work, so I used an iframe to put the widget in.

Here is the code:

<iframe src="http://yourwidgeturl.com" height="480" width="980" scrolling="no" frameborder="0"></iframe>

Everything should be pretty simple to understand. Replace the url with the url of your widget. Adjust the height and width to fit. Making scrolling and frameborder both equal to zero helps the iframe look like part of the page instead of a bolt on.