The most popular apps for the iPhone tend to have something in common, they are free. Most people prefer the free apps but will spend a small amount of money to buy apps that work well and are fun to use.

Wolfram Alpha has unveiled a new app selling for £29.99 that looks like a search engine at first glance, but is actually a database of information and computational services. You can ask the app questions like how's the weather and it will give you statistical information.

The downside is said to be that photos offered are wider than the iPhone screen making for lots of scrolling. Even in landscape mode, the images still spill over the screen a bit. The app is said to be good, but no more and is based on superb data.