Measured by market share, Apple’s (AAPL) iPhone continues what research director Paul Carton characterizes as “explosive growth.” Apple’s slice of the consumer smartphone market is now 23%, having grown 6 points since September and more than doubled since the introduction of the iPhone 3G in June.

Research in Motion’s (RIMM) market share, meanwhile, has leveled off, while Palm’s (PALM) seems to be circling the drain. See the chart below:

The picture going forward, however, looks very different. The ChangeWave survey was conducted between Dec. 9 and Dec. 15 — following the release of a slew of new BlackBerry products that culminated in the Storm, RIM’s answer to the touchscreen iPhone.

When the participants who planned to purchase a smartphone over the next three months were asked which kind they hoped to get, 39% said a BlackBerry — up 9 points from September. Meanwhile, the wave of enthusiasm that greeted the iPhone 3G seems to have settled down; today, only 30% plan to buy an Apple smartphone, down 4 points from September and 26 points from June’s peak. See below:

“So as we approach the 1st Quarter,” Carton writes, “the ball has shifted back into BlackBerry’s court.”

But there’s an important difference between the iPhone’s spike in interest last June and the BlackBerry Storm’s December surge.

iPhone users, on the whole, have been extremely satisfied with their new toys. Storm owners are considerably less so.

For comparison purposes, Carton has stacked the Storm’s favorability ratings against the original 2G iPhone, using results from a July 2007 survey taken less than a month after the iPhone’s initial release.

As the chart below shows, the original iPhone — with all its flaws — drew a “very satisfied” rating (77%) that was more than double the BlackBerry Storm’s (33%). More importantly, says Carton, the Storm’s “unsatisfied” rating (14%) is three times higher than that of the original iPhone (5%).

Carton also notes that 4% of new Storm buyers report that they’ve already returned or exchanged their unit or are “very likely” to return it. Another 7% say they are “somewhat likely” to return or exchange.

“A key question for RIM,” Carton concludes, “is whether their new BlackBerry products are strong enough to capitalize on the increased consumer interest.”

From the Changewave Alliance Web site:

ChangeWave runs a proprietary network of 20,000 highly qualified business, technology, and medical professionals referred to as the ChangeWave Alliance. Alliance members are credentialed experts in leading companies of select industries who spend their everyday lives working on the frontline of technological change. (link)