How big was Apple's biggest quarter?

????The fourth in a series of previews of Apple's results for the first fiscal quarter of 2010

????by Philip Elmer-DeWitt

????Two weeks ago we sampled analysts' expectations for Apple's (AAPL) iPhone, iPod and Mac sales in the fiscal quarter that ended Dec. 26.

????Today we look at the bottom line — revenue and earnings per share — for what Wall Street expects to be Apple's biggest quarter ever.

????This exercise is a bit more complicated because of accounting rules –- since revised — that required Apple to recognize iPhone revenues and associated costs over a 24-month period. Under the generally accepted accounting principles (GAAP) that expire next December, Apple has been reporting revenues that are as much as $3.79 billion lower than its actual (non-GAAP) revenues. (See The day Apple released its iPhone revenue bomb.)

????[Estimated Q1 2010 GAAP revenue in the chart above is the Street’s consensus as reported by Thomson Financial. Q1 non-GAAP revenue is the consensus of estimates from the analysts we polled. Pre Q4 2008 non-GAAP estimates are courtesy of Bullish Cross's Andy Zaky.]

????As expected, there is a wide discrepancy between the high and low estimates — nearly $1.3 billion for GAAP revenues and more than $1.5 billion for non-GAAP. (See below the fold.)

????But even the most bearish estimate, from Morgan Keegan's Tavis McCourt, has non-GAAP revenues growing nearly 18% year over year. The most bullish analyst, Broadpoint AmTech's Brian Marshall, is looking for better than 37% growth.

????We’ll find out whose numbers were closest to the mark in a week when Apple reports its Q1 earnings. Tune in here after the markets close on Monday Jan. 25 for our report on Apple’s earnings and coverage of its conference call with analysts, which begins at 5 p.m. ET (2 p.m. PT).