Apple has surpassed Google in market capitalization as of yesterday. Google stands at $157.23B and Apple at $158.84B. The news made its round quickly through the Apple focused blogs.
To compare Apple with Google is in my mind not really making sense. I rather see Apple competing with Microsoft. Microsoft stands currently at a market capitalization of $254.83B.
I see a chance that Apple can catch even Microsoft in a not that distant future. Microsoft will have to really change dramatically in the OS area to be able to stay on top and this will take time.