Intel is planning on announcing a new server chip early next week and if the early details are correct, it will be an 8-core Xeon.
The event is scheduled to take place on May 26th, and the new processor is codenamed Nehalem-EX. It is expected that this chip will take the place of the six-core Dunnington processor as king of the hill for Intel's server chips.
There aren't any speed specs on the chip yet but those should be available early next week when Intel holds their announcement event. All that we know at this point and time is that the chip will be able to execute 16 threads at once, it packs integrated power gates for lower power consumption, and Intel has crammed 2.3 billion transistors inside it.
Intel says that the Nehalem-EX is intended for servers that use more than two processors. At the conference, Intel is expected to discuss how the Nehalem-EX "raises the standard in cost-effective RISC replacement solutions."