Don't know if this has been posted already (searched and found nothing) but I was taking screenshots today and held down the PS button too long and a menu popped up with settings for brightness, music volume, disable microphone, and prioritize chat auto (party). I just figured I'd share this with others who may have not known about it. I thought it was pretty cool.
It's under brightness section of the PS Vita User's Guide
No news or anything hasn't covered any secrets or whatever yet, we'll have to wait till like after tomorrow so then they'll probably post their experiences.
Buuuuuuuuut, I think there's one website that covers on that secret. Check it out: http://www.edepot.com/playstation.html#Programming