What do Safari, Chrome, iPhone, and Android all have in common? They use Webkit as their html rendering engine. This has a bunch of nice side effects for mobile developers, the nicest of which is you can do at least 80% of your mobile web development on the desktop if you use Chrome or Safari. Since I'm on linux, I use Chrome, and it's awesome that all the mobile libraries (like Sencha Touch, jqTouch, etc).
I wrote a proof of concept Sencha Touch app that works almost exactly the same in Chrome as it does on my Nexus 1. However one of the things that bugs me is that the browsers don't honor the META viewport directives, and I seem to always get weird scrollbars showing up and ruining everything. so I wrote a little scriptlet that will pop up a window with the current page in 320x480 and without scrollbars.
Drag this to your scrollbar and then click it and it will give you an iphone-sized scrollbar-less window to test your moble app with. You can use my resume app above to see what I mean.