If you're a graphic designer, hopefully you're familiar with WhatTheFont, the essential service from myfonts.com that helps identify a font from a photo or other bitmap image. Now, MyFonts is bringing that power to the iPhone.
With WhatTheFont for iPhone, you can take a picture using the iPhone's camera, and use the WhatTheFont to identify the font in the image. No more guessing -- or even waiting until you get back to the computer. WhatTheFont is even useful to iPod touch users -- the software identifies fonts in images saved from Safari, screenshots, or other images in your photo library.
WhatTheFont requires internet access to work, since it connects with myfonts.com to perform the image analysis. It's free, and available in the App Store.