They'll give you stock quotes and financial news, monitor your investment portfolios and bank accounts, and even place trades. Many of the best programs, including most of those discussed here, are free.
Why should you spend time downloading applications? Theoretically, you could use the phone's Web browser to visit sites directly. Trouble is, you might have to wait minutes for a site to load, only to find that its text and images aren't formatted for your phone.
SplashMoney: For $9.99, this budget application enables users to monitor their online bank accounts. The "reports" function can convert your transaction history into a written summary or color-coded pie chart. SplashMoney also offers a downloadable computer program for $19.99 that can synchronize its data with the information stored in the iPhone application. Cheaper budget applications are available, but SplashMoney's useful features and simple interface make it a good bargain.