Below are listed five free applications for the iPhone that are exceptionally useful for the creative type and that all designers should have.

Units
Sometimes the best design is simple design. This app is one that I use very frequently for all sorts of things, whether when in the workshops, doing research or just in general conversation.

At its most basic it is a conversion tool. Pick any sort of category; length, time, weight, speed, and convert one unit into every other format. Instantly millimetres can be changed into miles and hours into milliseconds. Exceptionally easy to use, simple and a necessity for designers.

Wired
Almost all products since the turn of the new millennia have had a microchip in them somewhere, and those that don’t probably will do soon. Because of this, it makes sense to keep an eye on the latest innovations in technology related products.
With reviews, videos and my personal favourite WIRED blogs, this is a brilliant way to keep on top of tech and inspire you on your next project. It is also a great read when you are sat on the bus in the morning rush hour.

TED
Speaking of inspiration, this is the ultimate source of design related inspiration you will find either on the net or on the iPhone.  TED frequently post talks by creative individuals on a whole range of topics; from inspiration to why they chose to do something in a particular fashion.  All of the videos are well worth a watch and work remarkably well on the iPhone, meaning you are never short of known designers to influence your work.

Bump
Social networking always comes across as sounding dirty. It sounds like something you do to get ahead rather than because you want to get to know people. It isn’t. Bump is a little application that helps you with the networking side of your life.
The way that it works is, like most of the best apps, remarkably simple. You meet someone with an iPhone, you make sure that they have bump too, then you ‘bump’ the phones together. This swaps your contact details, much like handing out a business card.

SketchBookX
There are lots of drawing apps out there, all with varying features and interactivity.  This though is the best one I have found thus far.  The little brother of the £1.79 SketchBook Mobile, this drawing app is like Photoshop for the iPhone.  You can zoom, you can use varying brush sizes and colours, you can even do layers.  Want to do an illustration on the fly? This is the app for you.