A4 Specs

Wikipedia now has a page on the Apple A4 SOC (system on a chip) with some specifics. It appears that it's a ARM-A9 multi-core chip combined with a PowerVR VXD. The article seems to suggest that OpenGL ES 3.x and OpenCL are both possibilities with this chipset.

No matter how you slice it, it's pretty fast for a mobile device and this bodes well for the next generation of iPhones if they can scale the A4 to the iPhone.