The PSP, by this point in its life, has 2 games that sold 2 million in the Americas, and 8 more that sold over a million.
The 3DS already has 2 games that have sold over 2 million, and the 3DS already has 8 other announced/released games that will/have sell at least a million. (Pokemon, Smash Bros, NSMB2, Orcarina of time, Paper Mario, Luigis, animal crossing, and Nintendogs.
That's right, the 3DS already has as many announced system sellers in the Americas as the PSP.