If you go to Google Finance on your iPhone or Android via the mobile browser, it looks a lot like an app. You can enter a ticker symbol or company name in the search box at the top to generate a current price and stock chart. Three buttons on top let you switch from a market view to your saved portfolio to news.
The new mobile-friendly design just launched yesterday. (It is still catching up to Yahoo Finance, which has been mobile browser friendly for a while). The new mobile Google Finance presents most of the same information you can find on the main Website in a single, scrollable column: recent quotes, market charts, financial news headlines, a visual summary showing how different sectors are doing, and a list of gainers and losers.
Google Finance is also linked to other Google properties. Along the top, Finance is shown as a tab with other Google search properties such as Web and Images. When you do a search for a stock price or company on Google's regular mobile search page, Google Finance results appear and take you into the Google Finance mobile experience.
Google Finance also has an Android app, but no dedicated iPhone app. If you are on the iPhone, the best app for Google Finance is now the browser.