Are you busily designing web apps for the iPhone, but are a little nervous because you don't know what they will look like on it (since the iPhone isn't out yet and all)? Marketcircle, makers of the Daylite Productivity Suite, have just the app for you and best of all it is free (and will eventually be open sourced).
iPhoney is a little app that simulates web browsing on an iPhone. It uses Webkit (though for the best experience I would imagine you should install the Safari 3 beta) and requires OS X 10.4.7. iPhoney lets you rotate websites, as you would be able to do on the iPhone, show and hide the location bar, and even set the user agent to that of the iPhone (I suggest visiting as many Mac websites as possible so they get excited about iPhone visits in their logs). The cool thing about this app is that it is a pixel perfect representation of the iPhone. That is to say that the app will display websites using the exact same number of pixels as will be available on the iPhone's screen.
And just in case you were wondering, multi-touch is not included.