Berkeley Geochronology Center http://www.bgc.org/
Non-profit scientific research institution dedicated to establishing the history of the Earth, its various inhabitants, and its interactions with the rest of our Solar System, throughout the 4.6 billion years of our Planet's existence.
Geochronology Working Group at Vienna University http://www.univie.ac.at/geochron/
Uses radiometric dating and classical geochronological methods to constrain the timing of geological processes, primarily in the Eastern Alps, the Carpathian - Pannonian region and adjoining area, and the Bohemian Massif. Includes descriptions of several isotopic techniques.