MSFT has more than double the market cap of APPL, but looking at the revenue and earnings growth that may get wiped out in 3-5 years. Apple's revenue is growing at 33% a year vs. MSFT 12%, and Apple has been growings its profits an incredible rate of over 100% for the past 5 years, versus a very respectable 20% for MSFT. APPL is still very undervalued at it's current growth rates. It may have a PE that is double of MSFT, but it's profits are growing 5 times faster.
I suppose the closest analogy might be back when MSFT had its IPO.