Most likely it'll be the same as the iPhone: the iPad 3 costs the same as the iPad 2, and the iPad 2 is available at $100 less or something (perhaps with a cut to 8GB?). People looking for an iPad buy the 3, people looking to save money or just buy a cheap tablet buy the 2.
Maybe we'll see a jump in capacity too, with the 3 going to 32/64/128GB and the 2 staying at 16.
This is just an educated guess of course, nobody really knows outside of a select few at apple. We'll hear in a month or two.