Google Mobile App
Google's iPhone app is a must have tool for your phone. It lets you quickly perform searches of data stored on your iPhone as well as the web and also offers up location based results, which is handy if you're searching for a local cab company or pizza delivery place. Plus you get quick access to web-based applications like Google Talk and Google Docs. It's worth downloading it just for the voice search feature which never fails to impress the less technically literate!
The BigOven app lets you search the company's massive online database of 160,000 recipes ranging from lasagne to rhubarb crumble. You can even enter ingredients separated by spaces and it'll suggest dishes you can conjure up using what you've got to hand. You can mark recipes to permanently store them as favourites or tag interesting ones as ‘Try Soons'. In short, it's ideal when you need to look up how to boil an egg or make an omelette. Only kidding.
As well as putting together an iPhone-friendly layout for its website, eBay has also created an iPhone native application. It's a matter of personal taste, but we prefer to use this app to track our bids and manage our profile as we find it quicker and a bit more straightforward to use than the online site. However, there are a couple of limitations: you can't create a listing on your iPhone and you can't use the application to message other eBay users, but other than that it's a great little app.
So there you have it. We think this list provides a good mix of essential apps, interesting ones and some downright frivolous ones. If you want to check out more then take a gander at Andy's list of personal favourites, or feel free to post your own selection on the Comments page.