The info below is off Wikipedia and I found it kind of interesting. It may not be entirly accurate, but the link to the whole Wiki is below anyway.
Conroe XE By the end of 2006 Intel plans to introduce the Core 2 Extreme X6900, which is slated to clock at 3.2 GHz, while keeping the same FSB speed, L2 cache size, socket, and TDP.
According to leaked info, Intel is to release another Conroe XE in the 4th quarter of 2006, model X8000 with 3.33GHz and 1333MHz FSB QDR.
Kentsfield Kentsfield is the codename for the first quad-core version of the Conroe processor. According to HKEPC website, Kentsfield will be launched to the OEM market in Q4 2006.. There have been Kentsfield engineering samples spotted on eBay Taiwan.
Allendale An E4300 Allendale (1.8GHz, 800MT/s FSB) will be released in the 1st quarter of 2007.
Merom A second wave of Merom processors featuring an 800 MT/s FSB and using the new Socket P is expected to launch in April 2007.  These chips will be part of the platform codenamed Santa Rosa.