After stating a few months back that the release of the Dual Core Pentium D was a bit of a rush job, Intel has put some refinements on their chip and is releasing the next phase of the D line. The new "Presler" Core processors are quite different from their Smithfield Predecessors. The 65nm process is being used to manufacture them, giving the P4 a much needed reduction in heat output. The design has been changed as well, to actually have two separate processors on one package, each with their own whopping 2MB of L2 cache. The new chip also supports Intel's VT technology which they talked about a lot at this years IDF.
Though performance wise there is not going to be that much of a difference between the Smithfield and the Presler (aside from cache-heavy uses). Having independent L2 cache for each CPU will be a great boost, however, and the reduction in die size makes the CPU more attractive. The 900 series CPUs will be appearing shortly.