Two out of three of the emails I receive about sacred music I refer to the MusicaSacra forum. This forum works in real time to answer questions about urgent issues that arise week to week, but also operates as a massive archive of many hundreds of issues related to Catholic liturgy. In its few years of operation, it has become the web's treasure trove of information on Catholic music, both serving and educating at all times. It even serves as a place for connecting parishes with music directors looking for positions.
The Forum has recently undergone a beautiful upgrade, thanks to the long efforts of Richard Chonak. If you have never visited, you need to. It is helping the reform every day.