I'm currently looking at tools for making distributed programming tractable. NesC is one I've been keeping an eye on, although it is targeting much more constrained systems than I am currently interested in. Here are a few more worth checking out:

Bloom (also from Berkeley, there must be something in the water)- http://www.bloom-lang.net/

Opis - http://perso.eleves.bretagne.ens-cachan.fr/~dagand/opis/

OPA (proprietary) - https://mlstate.com/

Peerium (proprietary, yet to be revealed) - http://www.peerium.com/

If anyone knows of similar efforts I'd love to hear about them.

Bloom HN discussion thread:

http://news.ycombinator.com/item?id=2421636

I did my bachelor thesis working with NesC/TinyOS. It is a pretty interesting platform, with an interesting take to component-based design and concurrency (i.e. shared state, with race conditions statically determined by the compiler).

I recall at the time they wer working on a 1.2 release, I guess that did not go too far.

EDIT: ah files and VCS are updated, although the home page is not :)

Latest release is 1.3.2 which came out in August 2010.

as far as I can recall NesC and TinyOS has been going hand in hand. I believe one of the issues in advancing NesC is finishing TEPs for TinyOS