I don’t know any tutorials, but I can tell you it depends!
Use the channel mixer, check grayscale, then adjust the red, blue and green to get the image where you want it.
Remember the totals for all sliders added together should total 100.
After producing the BW image you like, I suggest going to mode grayscale, then mode duotone. Select one of the brown colors to warm up the image. Once you get the curves to your liking, change the mode back to RGB.
Hm, I've never followed any tutorials for making B&W pictures.
I just desaturate (Ctrl+Shift+U) the picture and then go to Brightness/Contrast, reduce the Brightness value and increase the contrast. It becomes kind of grainy, but looks very good.
I've found that the easiest and quickest way and which also gives a pretty good result is to use a gradient map in Photoshop that goes from black to white.
Easy and quick - yes - but you have no control whatsoever over the end result. Better go to Action Central - www.atncentral and there you can download several Photoshop action sets that will give you much better results.