There are many many resources, in fact it may be overwhelming. I would start with the godesalco "planificador" or route planner and look at mundicamino and eroski websites for more detailed information. There are many of us who have walked the Vdlp and who have posted our stages, so you should scroll through that section of the forum.
In general I'd say the marking is great, the albergues are very good, and it's a wonderful walk. As Heikki suggests, you should be aware of the construction, which seems to be a moving target, north of Zamora. Opinions vary on how much this construction and the re-routing it produces will interfere with a joyful camino.
When are you thinking of going? Spring, IMHO, is glorious! Buen camino, Laurie