This means that, at least in terms of market capitalization, the only US company worth more than Apple is Exxon, at US$278 billion. Apple surpassed Walmart's market cap last month, and Henry Blodget pointed out this morning that Apple was already ahead of Microsoft via the 'enterprise value' metric (accounting for the companies' relative amounts of cash and debt).
Oddly, Apple's leapfrogging of Microsoft's market cap has had less to do with Apple's stock and more to do with Microsoft's; over the past 60 days or so, Apple's market cap has grown by less than US$10 billion, while Microsoft's has plummeted by almost $40 billion. No matter which way you look at it, though, Apple's surpassing of Microsoft's market cap is, just as the New York Times says, an absolutely stunning turnaround.
Not bad for a company that was all but on its deathbed in the late 1990s.