To quote: Thank you very much for your interest in the Developer Program for PlayStation Suite (PS Suite). The Developer Program for PS Suite will provide content developers PlayStation Suite SDK (PS Suite SDK), a set of development tools and software libraries.
We will release the open beta version of PS Suite SDK to content developers in April 2012 and the official version later this year. Contents developed with the official version of PS Suite SDK will be distributed through PlayStation Store and can be enjoyed on PlayStation Certified devices, as well as PlayStation Vita.
Please refer to the GDC 2012 presentation slides (PDF 4.7MB) for details.
Finally, from tthousand via PSX-Scene (linked above) on the SDK contents: