Convert is a new application, made by tap tap tap, that, as the name implies, converts various different units. The idea has been implemented many times before, most notably in Tapbots' "Convertbot", but tap tap tap (ttt) has created a very elegantly designed application that makes it quick and simple to convert many different units.

You can scroll through all of the available conversions by tapping on the icons at the left. The "magic lens" is what shows your current selection. It zooms in on your selection for better usability and shows you relevant information. The outlined star shape is a "favourite" button, allowing you to quickly change between your favourite units, by tapping the blue star button on the keypad.

After selecting the unit type, you can choose the specific units you want to convert to and from. By selecting a unit, you can enter a value to be converted and see the conversion occur in real-time. By tapping on the second unit, you can enter a value into that, rather than having to select both units again.

The "Currency" unit has a refresh button, so you can have up-to-the- minute conversion rates. Although this may not be a major feature, it's useful to get current rates, rather than having obsolete data.
 
Convert comes with a built-in calculator, meaning if you want to calculate something, you can do it straight from the app, as opposed to quitting and opening Apple's native calculator. The basic calculator features are also available to use in conversions.

Convert makes full use of iPhone 3.0's copy and paste feature, allowing you to copy your conversion's result by tapping and holding on the value you wish to copy.

Overall, I'd give the application a 10/10 (for its category). It makes conversion simple and nice to look at and implements all of its features far better than any I've seen before.
 
Convert is available in the iPhone App Store for A$1.19, as an introductory price. You can find tap tap tap's website at http://www.taptaptap.com/ and in celebration of Convert's launch, they are having a competition to win a custom ColorWare Stealth MacBook Pro (15"). Be sure to enter the "tweetblast" by going to http://tweetblast.taptaptap.com/