Wolfram have announced a product aimed at the new generation of quad core
This looks like a mini version of their GridMathematica product and will run
four copies of Mathematica on your computer, one as a master and three as slaves.
GridMathematica is a well designed product. The interesting question is
whether the market is there for small scale grid computing, given that some
parts of normal Mathematica (mostly numeric linear algebra) will already use
all four cores automatically.
I doubt that it exists now, but it will only grow and Wolfram is the only one
targetting multi-core technical computing at the moment.