Taken from Crackberry.com
Press Release: RIM Expands Application Ecosystem for BlackBerry PlayBook - ANDROID APPS on PLAYBOOK!!! | CrackBerry.com
HUGE NEWS! We've been talking about Android Apps running on BlackBerry's tablet since August 2010 (before the PlayBook was ever announced - jump to minute 52 in this podcast) and today we see that our intuition was dead on, and we know how RIM is going to go about delivering Android Apps on the QNX-based OS. In addition to announcing the long awaited C/C++ Native Development Kit for the PlayBook, RIM announced support for existing BlackBerry apps and Android Apps.
Basically it looks like there will be a few "app players" that will run the current BB applications as well as Andriod 2.3 apps.
Developers just have to re-package, code sign and submit to App World (copyright lawyer stuff I guess).
Currently, App World is free for new developers so no additional cost to sign up.