Eurogamer.es claims to have inside information on the PSP2 - that's the PSP
2, not the PSP Go - and essentially asserts that it will have (shockingly!) better graphics.
This will be down to the hardware using a quad core version of the low-power SGX543MP chip. Digital Foundry has a full rundown on the techy stuff. The site notes that "While specs like this are always subject to interpretation, these figures are a ballpark match for the original Xbox."
More
here. Original Eurogamer.es post
here.
File it under rumour for now, next to 'Michael Jackson is not really dead'.