Apple Inc.’s iPad may soon put a stake in the heart of netbooks, research analysts predict.

The momentum is rapidly shifting from netbooks to tablets, said experts at Forrester Research and DisplaySearch in notes issued earlier this month. And Apple’s iPad is leading the charge.

Although only about 3.5 million tablets will be sold this year, by 2012 the form factor will outsell netbooks, according to Forrester’s projections. By 2015, more consumers will be using slates like Apple’s iPads than use the diminutive, traditional clamshell-style netbook PCs.

“Tablet growth will come at the expense of netbooks, which have a similar grab-and-go media consumption and Web browsing use case as tablets but don’t synchronize data across services like the iPad does,” said Sarah Rotman Epps, a Forrester analyst, in a statement Thursday. “Consumers didn’t ask for tablets…, but Apple is successfully teaching consumers to want this new device.”

Within five years, tablets will account for 23 per cent of all PC sales — Forrester classifies devices like the iPad as personal computers, even though Apple CEO Steve Jobs does not — Epps added.

DisplaySearch’s shorter-term estimates on the iPad-versus-netbook battle were even more aggressive. According to the Santa Clara, Calif.-based firm, Apple’s iPad accounted for about 6.5 per cent of the netbook-tablet combined sales of 10.3 million units in the first quarter of this year.

But for the current quarter — which ends June 30 — DisplaySearch said the iPad would grab approximately 30% of the total netbook and slate sales of 9.7 million.

John Jacobs, DisplaySearch’s director of notebook market research, put the iPad’s grab into perspective.

“The last quarter of 2007 heralded the birth of the netbook (and) Q1 2010 signaled the birth of the slate PC, and possibly by extension, the beginning of the end of the netbook,” he said in a research note posted to the company’s site.

Apple’s iPad has the tablet market to itself at the moment, but Jacobs doesn’t think that would last. “Apple has ported their successful iPhone app business model to the iPad, (but) Android-based phones followed in their footsteps and will surely do the same with slates,” he said, referring to the wave of Android-based tablets that were launched or previewed two weeks ago at the Computex trade show in Taiwan.

“In the second half of the year, as additional slates are launched, the clamshell-style netbook could continue to lose share,” Jacobs added in the research note.

Two weeks ago, Apple said it had sold 2 million iPads in the first two months of availability, a figure that put the tablet’s sales on a 7.6 million unit pace for the year.

One Wall Street analyst believes that Apple will do considerably better than that.

“Due to better than expected demand trends, we are raising our iPad units to 2.5 million in (the quarter ending) June 2010, 10 million in (calendar year) 2010 and 17 million in 2011,” said Brian Marshall of BroadPoint AmTech in a note to investors on June 1.

By Marshall’s forecast — and using DisplaySearch’s estimate of 9.7 million netbooks and tablets sold in the second quarter — the iPad will account for almost 26 per cent of the combined netbook-tablet market, slightly less than DisplaySearch’s prediction.