While Digging away through my shouts on Digg, I came across this very interesting article on noupe.com, listing 21 iPhone apps that can help you boost your productivity if you are a blogger, designer or freelancer.
As an example, there are colorpickers in the list, which will give you the colorvalue of your selection in different notations, there is the wordpress app, which will let you post new articles on your wordpress.com or selfhosted wordpress blog, there are texteditors in different flavors and shapes, and there even is a VNC interface, so you can use your iPhone to work on your Mac, Windows or even Linux machine.
You can find the article here: http://www.noupe.com/tools/top-20-iphone-apps-for-bloggers-designers-freelancers.html