It’s already April, and Apple has yet to start making large-scale purchase orders for NAND flash memory for 2008, according to a report issued Monday by iSuppli Corp. By this time last year, Apple had already ordered huge quantities of the stuff.

Apple (AAPL) looms large in the NAND flash market. According to iSuppli, it is the world’s third-largest OEM buyer of NAND flash, which it uses in iPods, iPhones and solid state disk drives for the MacBook Air.

Based on the lack of new large-scale orders — and on a February iSuppli report that Apple had “slashed” its expected 2008 flash growth forecast — iSuppli cut its own forecast of revenue growth for NAND flash memory this year by about two-thirds on Monday. iSuppli had previously forecast NAND revenue to rise 27 percent to $17.9 billion. It now expects revenue reach $15.2 billion in 2008, up only 9 percent from 2007’s $13.9 billion.

iSuppli had earlier predicted that Apple’s spending on memory would jump 32% this year to $1.6 billion. The firm now projects the company’s spending will increase only 12% to $1.4 billion in 2008, up from $1.2 billion last year.

iSuppli’s February report of “slashed” orders had surprised Apple watchers and didn’t help its share price, which had dropped 60 points from its December high of over $200 per share.

But the market seems to have shaken off iSuppli’s latest report, perhaps because demand for Apple’s products is so high. Apple can’t make iPhones fast enough to supply demand in the U.S. (see here) and interest in the next-generation 3G iPhones seems to grow every week. Meanwhile, Apple’s MacBooks are moving briskly and even iPods sales, which had slacked off, have picked up in the wake of the shuffle’s February price cut.

If Steve Jobs plans to sell 10 million iPhones in 2008, let’s hope he’s got the flash to put in them.