Sony will never do this. They never came up with something innovative for the PSP since the PS3 came out, only lame PSP 1000 design updates each year.
I do not expect to see anything special, and if they did, Apple or Nintendo would have already added it long ago. Sony is living in 2004. They said in the keynote "the PSP is very strong, it'll last for many years".
2011? Early 2011? I'd say late 2011 or 2012 at least. And if they did the PSP Go was a fail. They could have waited to bring out the PSP Go. They could have announced it as a PSP2 with hardware upgrades at E3 2010.
The PSP Go wasn't really necessary, the PSP Go has the same hardware features as the PSP 3000, the same capabilities as the PSP 2000 and the same functionality as the PSP 1000.
I personally guarantee you that there is a PSP2 in the making and that we will see/hear way more about it in 2011.
PSP Go, admittingly, was a huge failure. It could have been a huge success if one thing was done right though, price.
If the PSP Go was $149, and new games launched at $19.99 as a standard, people would grab these off the shelf like hotcakes.
Here is to hoping that the 3DS isn't overpriced, Nintendo can be quite.... greedy.... despite their ability to amaze us every year with their unrivaled game releases.
(mario galaxy 2 - GOTY 2010, mass effect 2, red dead redemption, crysis 2 can all suck it)