Pollster.com: 2008 Ohio Presidential General Election: McCain vs Obama
Pollster just released a flash application that allows readers to make their own poll composition graphs. You can control which polls are considered, who is shown, the date range, the amount of smoothing, and so forth. Not perfect, but a good leap forward. For example, I think it would be better to have more smoothing before the conventions, but less smoothing afterwards since the news -- and polls -- have been coming thick and fast since then.