A little over a year ago, I wrote a piece examining the valuation of the stock of fallen education star Apollo Group (NASDAQ:APOL). If you like, you can read the entire column here, or you can settle for this abridged version: Despite having fallen nearly 25% from its $98 high hit on June 8, 2004, at the $75 and change that its shares fetched in early October 2004, Apollo was still not quite a buy.

Since that article came out, Apollo shareholders have lived through an interesting year. Not long after I wrote the piece, Apollo caught an updraft and came very close to breaking the $90 barrier once again, before drifting right back down to where we started. Which reminds me of the conclusion I made about Apollo back in October 2004: "The valuation isn't quite as low as we'd like it to be, but given time, Mr. Market may discount Apollo further."

With Apollo now trading nearly 20% lower than when I made that comment, and the company's fiscal 2005 earnings numbers out -- complete with cash flow statement, I might add (thanks, guys) -- now looks like a propitious time to see whether the valuation has finally become attractive for Foolish investors.

From a basic generally accepted accounting principles perspective, Apollo had a fine year. Revenues grew 25% year over year, and earnings were up 60%. Can't beat that with a stick. However, from a free cash flow perspective, things don't look so pretty. It's not gruesome yet, mind you -- Halloween is still a few weeks off. But with $462 million in free cash flow in fiscal 2005, against $470 million in fiscal 2004, it seems that not only did Apollo not grow its real cash earnings as fast as its GAAP numbers suggest, it actually took in less cash this year than it did last year.

Then again, Apollo is also selling for $2 billion less than it did last year. And at $11.2 billion in market cap, this erstwhile fast grower looks attractively priced at just 24 times free cash flow. The real question is whether it will, in the years to come, be able to once again grow its cash as quickly as it does its GAAP earnings. If the answer to that all-important question turns out to be "yes," then today will mark the moment that Apollo finally entered the realm of bargain territory. If cash generation continues to contract, however, well .

It pains me to say it, but once again, I think the prudent course is for Fools to hold off on Apollo, and not buy until free cash flow has resumed growing.

Judge where Apollo might go from where it's already been:

Fool contributor Rich Smith has no position in Apollo Group.