None of this is substantiated, but it comes from late development kit leaks. The conference today lines up very well with these leaks.
The CPU is rumored to be a 8 core with 1.6ghz approximate clock speed. The only reason they'd go for a low clock speed like that is if AMD is deriving it from their Bobcat line of processors. AMD's recently announced their Jaguar cores. http://www.techpowerup.com/180394/AMD-quot-Jaguar-quot-Micro-architecture-Takes-the-Fight-to-Atom-with-AVX-SSE4-Quad-Core.html I think that's a positive myself, as a 1.6ghz jaguar core will probably blow the 3.2ghz PPC dual issue core from the PS3/360 out of the water. Branch prediction and lots of other nice features that you get from having a more modern processor and not some weird RISC to the max core.
If they are Jaguar cores, then there will be 2 compute modules with 2 megabytes of L2 and 4 cores each. 4MB of cache total.
The alternative would be a 4-module Piledriver core (2 cores per module) thing, but the Jaguars make more sense. The only thing that would indicate Piledriver would be that earlier dev kits utilized A10 APUs, and those have 4 cores of Piledriver on them. The rumormongers stating Bulldozer are completely off their rocker and should be ignored. 
The GPU is rumored to be a 7970M chip, which would line up with the Jaguars in indicating that they're building this from Laptop style PC components. Should be fairly energy efficient for how much power. a 7970M is roughly the same as a 7850 or 7870 desktop card, but uses less power.
I'm really glad they decided to bump it up to 8gb. The rumors were that they were doing 4gig with 512mb allocated to the OS.
Rumors also say that the Xbox is using the exact same 8-core jaguar chip for its cpu, but using a different GPU.
As for price, the rumors are currently stating $400-530 range... one said $430 for the lower end and $530 for the higher end. Another rumor states $450 for the only model. I imagine that they're holding off on announcing pricing until Microsoft does.
Edit: Here's another reason for Jaguar over Piledriver. A Jaguar core is 3.1mm^2 each. If you say that the L2 cache takes up the same amount of space as the cores in a CU, then that's 48mm^2 for an 8-core Jaguar. The 7970m is a 221mm^2 chip. Together they're only 269mm^2, huge, but not out of the realm of possibility for a single die APU.
http://www.anandtech.com/show/5831/amd-trinity-review-a10-4600m-a-new-hope
This page has a Trinity die picture. the CPU part seems to be 33-40% of the total die size. If we low-ball this and say 33% of a 246mm^2 die, that's 81mm^2 for 4 cores. That means 162mm^2 for an 8-core piledriver. more than 3x as much as the Jaguar. Can you imagine a 383mm^2 die? That'd be ridiculously expensive to manufacture.
