Our May 12, 2009 meeting, presented by Marvin Sable was all about GREP. Here are some links gathered by Marvin for your reference:

http://www.indesignusergroup.com/learning_center/whitepapers/2008/indesign_grep_mmurphy.pdf (PDF download)

http://www.night-ray.com/regex.pdf (PDF download)

http://www.regular-expressions.info

http://livedocs.adobe.com/en_US/InDesign/5.0/help.html?content=WSa285fff53dea4f8617383751001ea8cb3f-6f59.html

http://www.rorohiko.com/greptutor/GrepTutor.html