want to read together this recent Bojowald paper? Time Dependence in Quantum Gravity http://arxiv.org/gr-qc/0408094 Bojo is at Albert Einstein Institute (AEI-Gölm) one of the premier places for QG. It looks like not too hard and it clarifies things about time in QG. So could be useful to assimilate. Besides Bojowald the other two authors are Pamapreet Singh (IGPG-Penn State) and Aureliano Skirzewski (AEI-Gölm). Meteor probably posted the link for this when it came out but I only just now realized the special value of it.