- New Scientist: http://www.newscientist.com/news/
- Eurekalert: http://www.eurekalert.org/pubnews.php
- Science Daily: http://www.sciencedaily.com/
- American Scientist http://www.americanscientist.org/
Others?
Is the AIP's Physics Update (http://www.aip.org/physnews/update/) big enough to count as a site?
What about the preprint archive at http://xxx.lanl.gov? Or Baez's "This Week's Finds in Mathematical Physics" (http://math.ucr.edu/home/baez/TWF.html)?