http://www.amazon.com/Volleyball-coaching-books/lm/RF40K3AARVSA6/ref=cm_lm_byauthor_title_full

There are a few more I would add but it is what it is.

In my experience, the best thing to do is to observe as much as possible and then cross correlate with the books. People teach different techniques and have their own reason for it. The USAV has a pedagogy with disagrees somewhat with say the Russian or Japanese volleyball orthodoxy so it is useful to talk to people get their ideas but think critically about ti to see if it fits your philosophy. One thing to keep in mind is that all the skills are inter-related, how you pass, where you tell the tesm the target is has an impact on what you do on offense. How you play defense, where the players are on the court in defensive transition has a huge impact on your transition to offense. So there is a need to look at all that judiciously.

Also ask questions of coaches that you have respect for. Most coaches, especially college coaches have pet theories and ideas about their system and their training. Many will be busy but will share their insights with you. Don't go up after a five game match against Nebraska or Stanford but if they are hanging out at tournaments, i.e. not sitting on the sidelines observing recruits, go up ask about their specific ideas. Be specific, don't ask: what is your serve receive formation. Rather ask about technique and ask about what their serve receive does for their offense and what they do in serve receive against a great server etc.