Mac sales, Apple's single largest revenue source, are expected to recover substantially for Apple's Q4 of its fiscal year.  With new iPods, the iPod sales slide is also expected to slow slightly.  However, some fear that iPhone growth is slowing and the numbers won't be enough to satisfy investors.

Last year Apple sold 6.9 million iPhones during this quarter, amid the recession.  This year's estimates predict sales of 7.5 million phones (taking the average of analyst figures).  Some are concerned by Apple's announcement in September that it had sold 30 million iPhones to date.  This could indicate that it had only sold 3.5 million iPhones by September, too slow a pace to reach its targets.  And while Apple is reaching into foreign markets like China, there are reports that it is having trouble handling demand in these foreign locales.

Hudson Square Research analyst Daniel Ernst states, "The driver is if the iPhone keeps selling well.  Mac is a huge part of the company and I think it's going to get better next year, so while there may be some risk in the iPhone sales for the quarter, people will take some solace in that the Mac sales are pretty strong."

With investment analysts sick of being embarrassed by bloggers posting higher estimates for Apple, many analysts began to raise their estimates in September.  Sanford Bernstein analyst Toni Sacconaghi writes in a recent research note, "Expectations for Q4 are high going into FY Q4, and we would not be looking to make a big bet on the quarter."

Rounding out analyst predictions, they expect a revenue of $9.2B USD, up 17 percent from a year before.  They expect 7 percent growth for Macs, at 2.8 million Macs.  IPod sales are expected to be down slightly -- 5 to 10 percent.

With IBM and Google also beating estimates, though, Apple won't be the only one in the club if it manages its usual surprise.  Thus, how investors take the news largely relies on exactly how big the surprise is -- for example in Google's case, it greatly beat estimates and its stock rose.

Apple does have one potential ace-in-the-hole.  It is rumored that it will be releasing a tablet PC sometime next year.  While no official confirmation has come from Apple, a wealth of information and pictures leaking onto the web seem to indicate that something is coming.