According to the sometimes reliable Digitimes, Apple is expecting to move 6-6.5 million iPads in Q1 2011, and 40 million over the entire financial year. Of this first quarter, their source says 300,000-400,000 iPad 2s will ship.
This calculation somes from the fact that Apple ordered 1.7-2 million iPads in January and February, but fewer in March, implying that they’ll be picking up the slack with the new iPad, and pulling back on the old one.
If Apple immediately drops the price on the original iPad today, you can bet they’ll still be a hot seller, especially if it’s a mostly under-the-hood upgrade.