Taking a page — albeit a tinier one — from the iPhone’s design is a new test version of the Opera Mini browser for cellphones. There are two important differences: The first is that people can get their hands on the free browser, officially named Opera Mini 4 beta, by visiting mini.opera.com, which also lists compatible phones. The second is that most phones that can run the browser have considerably smaller screens than the iPhone and don’t respond to taps of the finger (though those with touch screens will).