iPhoto+BW+Conversion

one technique and one technique only for black and white conversion, and it uses iPhoto: The saturation slider on its own results in a rather washed-out, infra-reddish monochrome image -- the colour balance slider adds really satisfying contrast and tone. It does this by changing the colour balance of the underlying colour image, but the results can immediately be seen in the monochrome image on screen. The tint slider does the same thing, but results vary hugely from image to image.
 * 1) Double-click to edit the photo in iPhoto (v6 required; I always use full-screen mode)
 * 2) Bring up the Adjust dialogue
 * 3) Slide the Saturation slider all the way to the left
 * 4) Slide the Temperature slider all the way to the left (towards blue)
 * 5) [Optional] Muck about with Tint and Exposure until I've got something I'm happy with