There isn't much info out on the device yet besides that it's a tablet, has a 9.4" screen, runs Android, is Playstation certified, and balances its weight more naturally for one handed use by have a "loop around" section on the back that puts more weight directly over the users hand and wrist, making it feel lighter, and less fatiguing. That loop also serves to give the tablet a raised angle to type on, while it sits on a table. The story is up at Engadget.
So far it's still just a rumor, but it's from credible sources, just like the Xperia Play was way back when that was first leaked.
This is interesting because I assumed that Sony was going to have the PSP2 be their PS/tablet hybrid, it sure is powerful enough, and with any decent OS can be marketed as such, but obviously Sony feels like those are two different markets.
So now Sony will have 4 Playstation devices on the market; the PS3, the PSP2, the PSPhone, and the PSTablet. Which is an interesting strategy, considering that the PSTablet will be able to connect to a TV sans the PS3.
The tipsters have a lot of praise for the device, saying it's the best looking device Sony has ever put out.
For now, the alleged ship date is Septmember for a price of $599, but both are subject to change.