Coinometer is a super simple iPhone app that lets you keep track of the Bitcoin pricing. It is designed to do one thing only and it does that excellently.
Coinometer features a really neat user interface that takes no time getting used to. When you start the app, it shows you the current price for 1 BTC, which is fetches from Bitstamp. If you own some BTCs, you can keep a track of how much you’re gaining or losing by adding how many BTCs you own and at what price you got hold of them. The app then keeps track of not only the current rate, but also calculates how much you have gained or lost on your existing quota of BTCs. The current price automatically keeps refreshing, although your own gain/loss numbers have to be manually refreshed.
Coinometer lacks a few features compared to Coins (which was quite similar to Shares) though. It doesn’t currently offer multiple currency support or a Today Widget. On the other hand, while Coins is a Universal app, it only lets you add how many BTCs you own, not the price you got them at. It also doesn’t display the current pricing for 1 BTC.
If you deal with Bitcoins, you should probably have both these apps, considering both are available Free on the App Store.