The Tablet Marketplace: Waging War?

Research In Motion's

PlayBook was introduced Monday, effectively diving into the market currently monopolized by Apple's

iPad, according to

. There will soon be other competition from Dell's

Streak (available now) and Samsung's Galaxy (not yet available). Apple has sold more than 3 million iPads since April, the Streak became available in June, the Galaxy should be ready mid-holiday season, and the PlayBook is scheduled for production early next year.