We just released a new CTP of Parallel Extensions to .NET: get it here.
Some relevant information is up on our team blog:
I'm really excited to see our entire stack finally shipping as one cohesive unit: the data structures we use throughout the implementation exposed publicly (what we now call CDS), a new scheduler built from the ground up, TPL and PLINQ better together, and lots more. We're still very far from the end of the road, and have plenty of cool stuff still in the works, but we've made a ton of progress in just 6 months since our last CTP.
Have fun and, as always, feedback is much appreciated.