New estimates keep coming in, and this time, Needham & Company Analyst Charlie Wolf expects Apple’s iPad to sell two million units in fiscal year 2010. That number will rise by another six million units in 2011.

Wolf believes the iPad will need a catalyst to see a hockey stick growth curve, similar to the iPod line of products with the introduction of the iTunes Music Store and the App Store for the iPhone. He doesn’t see that catalyst from Apple for the next 18 months. He also recognized that 2012 would probably be when Apple will see its iPad take off, but it’s beyond the scope of the researcher’s forecast.

Last week, we published a report citing ABI Research that expects to see tablet sales hit four million units. If these numbers are anything to go by, the iPad will be responsible for 50% of the shipped units in 2010. They also see tablet sales hitting 57 million units by 2015.