The main sources I've found are
http://www.attra.org/attra-pub/compost-tea-notes.html
http://www.attra.org/attra-pub/biodynamic.html
(which are overviews).

Im curious about others' experiences. I've started experimenting with it because I can grow a lot of comfrey, whereas I'd have to buy seaweed products. I haven't used it enough to be able to say what specifically it does; I'm assuming it's an abundant source of trace minerals (10-foot taproot!) as well as P and N.

I do know that it ferments to a spectacularly rank brew within a week or so, developing a white skin on the surface of the liquid, as the leaves melt into a green slime. The last time I made it, I let it ferment for a couple weeks. The current brew has been going for 3-4 weeks, since I haven't found the time to decant.