Note: This is a question about simulating the Browser on the iPhone, not simulating the whole device. I know that iPhone-device simulation is not possible o
I'll start off the answers:
Blackbaud labs have an open-source, Abode Air powered iPhone browser sim here:
edit: new link: ibbdemo2
(go to downloads link to get .air binary. You need Adobe Air installed)
Unfortunately it doesn't reproduce my particular problem, so it must be rendering differently.
You can simulate the iPhone user agent in Safari 5 if you set up the Developers menu item in Preferences>Advanced. The webkit engine in Safari 5 is similar to iPhone's browser so most of the HTML 5 stuff works the same. As a bonus the Developer's tab allows you to debug JavaScript and some CSS (not so well supported).
[I know the question's quite old now, but maybe my answer might help people coming in with the same query...]
I have found the Google Canary browser's emulator to be one of the best and quickest for testing browser compatibility issues on a windows machine.
It even emulates the iphone's 2x device pixel ratio.
Definitely give it a try and see if it reproduces your issue:
http://www.google.co.in/intl/en/chrome/browser/canary.html
To try out the emulation, hit F12 and below the usual row of dev tools, you will see the second row like in this screenshot...
Plus, it also renders many of the popular device browsers out there...
Hope this helps.
Try these. I tried this in chrome, and sites i visited loaded the non-iphone version. Maybe safari would be better.
http://www.testiphone.com
http://iphonetester.com
UPDATE: After further research, looks like these really only limit the screen size, and dont use the iOS Safari rendering engine.
I tried all of the options mentioned and didn't like them (basically because they don't show platform-specific components, which is interesting for demonstration purposes).
If this applies for you guys, I'd recommend http://www.browserstack.com/
Unfortunately, it's not free.