Checked the fan sights for the Stealers and Bills. Here is what they are doing:
Blocking Cookies (Internet Explorer) Instructions:
1. In your internet browser, click "Tools."
2. In the dropbar go to "Internet Options."
3. Click the tab 'Privacy.'
4. Click the button "Sites."
5. Add the link to the voting site to the 'Block' list.
6. Click "OK" (twice)
Firefox users go to Tools > Options > Privacy.
Under Privacy where it talks about Cookies, click "Exceptions" and add the URL link of the website, and click Block.
After you vote, close and reopen the website and you can vote again.
There is also a rumor that after you enter the code press the submit button as many times as you can before the page refreshes and you get multiple votes. Not sure about this.