Just in time for the first really scary hurricane of the season, Weather Underground is providing an iPhone-specific version of their mobile site that includes a tropical storm tracker. The mobile site URL is http://i.wund.com, and the tropical storm page can be accessed directly at http://i.wund.com/tropical.
As you can see in the screenshot above, the tracker shows the location, intensity, and other statistical information about each storm. In this case we're looking at Tropical Storm Gustav, which appears to now be a Category 3 hurricane. The full-screen view seen above requires a flip to landscape mode.
If you're an iPhone user and live in any location where tropical storms can be a hazard to life and property, you might want to add this site to your Home screen.