Intel has shown a research project to put 80 processors on a chip that will provide a teraflops of performance (compared to 4Gflops for today's 2GHz dual core Pentiums) in five years time. These 80 processors are floating point cores running at 3.16GHz, apparently, to get that performance, but I suspect that is a theoretical figure. If two cores at 2GHz produce 31W, imagine the heat off that lot (well over 1KW (ok 1.8KW) - sit round family and warm your hands!)
However, the ITRS semiconductor roadmap sees 79 processing elements on a chip by 2010 , but that is up from 23 this year and 32 next year (while Intel is still at, um, 2 - the quad part is two dual cores in the same package!).
Have a talk to Picochip in Bath, who today put 240 processor on a chip, and make them all work together for WiMax and 3G basestations in the home from companies such as Ubiquisys and IPwireless!
These are the ones who will drive to the ITRS predictions of 268 processing elements on a chip by 2015 and 878 (nearly a thousand processing elements on a single chip) by 2020.