Finally a solution for an animated weather radar. (thanks Zaphu) There currently two applications that can do just this, but it requires a nominal fee of $0.99. With the current reviews nearing the low 2 stars, I'm a little hesitant. The author of Radar-In-Motion has mentioned that he will accommodate the quirks that others have been complaining about which might make it worth it later on.
iWeathr is the best radar app for the iPhone that I have found so far. Navigate to iweathr.com and locate your nearest radar location. Note that you won’t be entering the city where you live but rather the location of a radar installation. For help finding the nearest one to you go here. This implementation allows both rotation and zooming in - very nice!
Another nifty weather iPhone web application can be found at http://iphone.my-cast.com/ It's a basic forecasting web-app but all that more powerful and simple.
*Update: kurt mentioned below that he prefers i.wund.com for it's simplicity and the mass information that is displayed on the iPhone screen for that particular location. I have to say that it definitely does show great information, but the moving map on iweathr.com is the basic one that is hosted by the government's weather website: http://adds.aviationweather.gov/radar/ which is the one that prefer using when scoping out the weather prior to flying. Thanks for the comments!