It's 'the new iPad', not the iPad 3. Apple is evidently going to follow the same pattern as it does with its computers and is doing away with a sequential numbering system.
So the next iPad will also just be 'the new iPad' the same way that every year we see 'the new MacBook Pro'. The iPhone will probably follow suit.
Apple is following the pattern that begun with the failure of the Apple III computer, which is to not name any more products "3". There was no Mac 3, iPod 3, or iPhone 3.
So the next iPad will also just be 'the new iPad' the same way that every year we see 'the new MacBook Pro'. The iPhone will probably follow suit.