Developer: Bloomberg Finance LP
Price: free Download on the App Store
For financial market news, Bloomberg is second to none. The iPhone app is an excellent resource for stock quotes and business news on the go, and provides a template on how a good news service should be ported to the iPhone.
Like the NYTimes app, Bloomberg features a bottom menu bar and a top content area; the app pre-loads the content areas, so that you can easily page from the headline list view to the the "markets" view without waiting.
Clicking on an individual symbol, such as the Nasdaq Composite index brings up additional information such as high, low and volume; and allows you to access the vast amount of historical data compiled by the Bloomberg service.
The app is free.