Downloading historical data in an iPhone application

I'm going through the terms of service and I'm not sure if this is acceptable use or not.  I am developing an iPhone application that downloads historical data and does some charting.  Specifically it draws a candlestick chart and overlays some other indicators over that chart.  I also have buttons that open a browser opens the relevant pages on the the Yahoo finance site for the stock being charted.  

I will not be charging for this application and would be happy to put any badges, logos, notices of copyright or trademark, indicating that Yahoo! supplies the data.