I study music information retrieval (MIR). Here are some of my bookmarks:

MIR Tools: http://www.music-ir.org/evaluation/tools.html

MIR How-Tos: http://www.ifs.tuwien.ac.at/mir/howtos.html

MIR Data Sets: http://grh.mur.at/sites/default/files/mir_datasets_0.html

MIR Toolbox (Matlab): https://www.jyu.fi/hum/laitokset/musiikki/en/research/coe/ma...

Million Song Dataset: http://labrosa.ee.columbia.edu/millionsong/

The "music" tag on Stack Overflow has some basic discussions on MIR: http://stackoverflow.com/questions/tagged/music