The support for Android applications is most intriguing. It's going to work like this: something RIM calls an application player for Android can be downloaded from BlackBerry App World. Developers can repackage their Android applications and have them signed and submitted to the App World. It works the same way for BlackBerry Java applications. Both of these players will run in a sandbox for added security.
"The BlackBerry PlayBook is an amazing tablet. The power that we have embedded creates one of the most compelling app experiences available in a mobile computing device today," said Mike Lazaridis, RIM's president anc co-CEO, "The upcoming addition of BlackBerry Java and Android apps for the BlackBerry PlayBook on BlackBerry App World will provide our users with an even greater choice of apps and will also showcase the versatility of the platform."
Aside from support for HTML5, Flash, and AIR, RIM is now also adding a native SDK, called... Native Development Kit. With this, developer can build "high-performance, multi-threaded, native C/C++ applications" using the GNU toolchains. Programmable shaders in hardware-accelerated OpenGL ES 2.0 are also available.
All this gives developers some pretty decent options, and the ability to get your Android application onto the PlayBook with minimal fuss seems like a major boon, and a serious competitive advantage over something like the Palm TouchPad.
Then again, you don't need a BlackBerry to check your mail on the TouchPad.