Lightroom evangelist/PM George Jardine has posted a free 37-minute video that dives deeply into black & white conversion. He writes,
In this video, I start by taking you on a brief exploration of some of the various conversion techniques that we all used back before there were better controls for creating good black & white’s from raw data. And I did this because I think reviewing those tried-and-true Photoshop techniques, helps set the stage for a better understanding of black & white conversion in general.
http://mulita.com/blog/?p=1244