The poll displays the server time, plus or minus the "offset" you have in your preferences. For Jazzo, the time is 3 PM, for you, Laurence, it's 12:00 PM. The forum server time is the important time to watch, since the forum software is managing the voting. When the server's clock says that it's time to close the voting, it will close the voting.
You can see the current time on the server by clicking My Stuff => My Preferences and scrolling to the bottom of the page. Near the bottom, you'll see a line that looks like this:
Current server time is: 04/10/08 06:58 AM
You'll notice that the server's clock is usually a few minutes off, but that's a different matter, entirely.