Conversion tools are great little apps to have on your iPhone or iPod Touch simply because of how useful they can be at the right time. With a few taps, you can convert such categories as temperature, speed, length and area. Some apps convert the basic, most used categories while others can convert just about anything you want to throw its way. HiConverter – A Comprehensive Unit Converter and Tip Calculator, developed by Chillingo, is just such an app. With over 3000 units and 108 categories to convert, the majority of users’ needs are more than likely to be covered.