As the market just begins to open today, Apple’s market cap crossed the $600 billion threshold. Today’s accomplishment comes just a month after the company hit the $500 billion threshold. The market overall is down.

To compare, Microsoft holds the record for the highest market cap ever of $619 billion in 2000 (over $800 billion in today’s dollars). At the time of this writing, Microsoft is sitting at a $250 billion market cap. If some analysts are to be believed, the AAPL train will keep rolling to a $1 trillion market cap in the coming years.

Apple now dwarfs the No. 2 company, Exxon, by a comfortable $200 billion. We are looking forward to April 24 when Apple will talk Q2 2012 numbers.