It is a smart move, since lack of apps could kill HP's WebOS and seems to be really hurting Windows Mobile7.
On Thursday, RIM said it plans to deliver what it called an "app player" for its PlayBook tablet that will provide an environment capable of running Android 2.3 applications.
My worry would be that it starts out running Android apps but then, like Firefox extensions, every major upgrade of either Android or the app breaks the app on the Blackberry OS. That on again off again bit would be irritating.