When it comes to useful apps, Skype WiFi for iOS is likely to be up there with the best of them, especially if you and your iOS device get out and about quite a lot.The idea is both simple and effective. Download the Skype WiFi app, sign in with your Skype account and make sure you have some credit in your Skype account. Done that? You're ready to go. Wherever you are, you can boot up the app and hunt for your nearest hotspot – it shouldn't be far as there are over a million worldwide. A single tap hooks you up, ready to browse, upload or download.You only pay for the time you are connected, not the amount of data you've chewed up. So watching iPlayer is the same as browsing sites, for example. Which is obviously good news for TV addicts who like a foreign holiday. Once you've finished, click 'Go Offline' and the browsing (and billing) will stop. If you forget to leave the connection, you'll be asked every half an hour – the length of the 'session'.You'll need iOS 4.1 to be able to use it and you'll probably want to check some costs in advance. See the Skype site for that, but as a guide, UK prices are between 3p and 13p per minute.