Here's how to pretend to be an iPhone. Why would I do this? Well its rather fast when the web site doesn't send all the undisplayable stuff down to you.
Also you can test the new html 5 gmail interface.
In Firefox you can download a plugin and after a restart iPhone is one of the defaults.
In Camino you can download the User Agent plugin which you have to manually place in
Restart Camino and you get an extra tab in the preferences window
Add the following text and you are good to go. For some reason I was not able to 'add to presets'.
Mozilla/5.0 (iPhone; U; CPU like Mac OS X; en) AppleWebKit/420+ (KHTML, like Gecko) Version/3.0 Mobile/1A543 Safari/419.3