I'm not too tech savvy so I hope there are others here that could fill in some blanks for me, correct me where I'm wrong, and/or put in their 2 cents but here is my take on what to expect from the 3DS in terms of specs. Before I continue, I do have to warn everyone that I did this search in haste and only used Wiki for the most part which is not the most reliable place for accurate information.
First, lets establish the 3DS's competition. I believe its main competition are , obviously, Apple's new Iphone 4g and Sony's PSP2. The 4G Iphone is due to release June 24 and the PSP2 is anyone's guess but I'd say anywhere from fall of this year to early 2011. The 3DS will release after the 4G Iphone and anywhere from before, on, or after the PSP2 so I assume its specs should fall in between its 2 competitors. IMO, the 3DS's specs should fall between, at the least, the 4G and slightly less or similar to the PSP2.
From my quick googling, I've come to find out that the 4G is using Apple's new A4 chipset which consists of an ARM Cortec-A8 CPU core, which is 1 Ghz, paired with a PowerVR SGX 535 GPU which, supposedly, can do 28 Mpolys/s, 500 Mpx/x @ 200 Mhz with a max memory band of 4.2 GB/s.
The PSP2's guts are unknown at this moment but rumours are making the rounds that the GPU in use is a PowerVR SGX 543MP8 (MP8 standing for 8 cores out of a max of 16 cores possible with this chipset) which, supposedly, puts out 532M poly/s and fill rates in excess of 16 Gpixels/s @ 400 Mhz. There are no rumours I've been able to find on what the CPU could be on the PSP2 so I'll not comment on that.
Just for sh*ts and giggles, I also looked up the Tegra 2 for comparison's sake. It has a Dual-core ARM Cortex A9 MPCore and its GPU is supposed to be slightly ahead of the PowerVR SGX 540 series of chips.
So basically, if all this information holds true, I believe the hierarchy goes something like Apple's 4G < PSP2 <= Tegra 2. Based on my assumptions the specs of the 3DS should lie between an ARM Cortex A8 and multi core A9 for the CPU. For the GPU, it should fall between a PowerVR SGX 535 and a PowerVR SGX 543MP8.
Now, like I said earlier, I'm not tech savvy so I have no idea if any of these numbers are true or any good. I don't really know what these numbers mean in relation to what the user will be able to expect/experience. Here are my Wiki links
Apple's A4http://en.wikipedia.org/wiki/Apple_A4 PowerVR (show's NEC is a licensee of the PowerVR series 5 chips SGX and the PSP2 rumour)http://en.wikipedia.org/wiki/PowerVR#Series5_.28SGX.29 Tegra 2http://en.wikipedia.org/wiki/Nvidia_Tegra#Tegra_2xx_series