It is assumed that you know how to create a Google Form. If not, look here: http://www.youtube.com/watch?v=9VBGSaB3URs.
Below I have embedded a form with a poll question (type: multiple choice).
Select an option and press submit to test!
The 'show previous responses' link that is displayed after pressing submit (https://docs.google.com/forms/d/1fV6lKvRfiOQZkJTCbQjA4UamRSaNCUF_h_vxhLto0AA/viewanalytics )
takes you to a graphical summary of the responses which you can then embed using the iframe embed gadget as I have done below.
*** not currently working - new Google forms seems to have broken something ***
Chart from 'publish' HTML
In this spreadsheet, the poll responses are recorded in Sheet1, column B. The possible responses are listed in this sheet in cells A2-A5.