Got this in one of my daily emails and thought it might be interesting to someone.
Greg Gorman's Photoshop CS Recipe for Black and White Conversion
1. Open a color image in Photoshop in either 8 bit or preferably (in Photoshop CS) 16 bit.
2. Under the Image menu, choose Mode > Lab.
3. Click (Highlight) the Lightness Channel.
4. Under the Image menu, choose Mode > Grayscale (discard color information).
5. Command/Control Click on the Gray Channel (to load the selection).
6. Under the Select Menu, choose Image > Inverse.
7. Under the Image menu, choose Mode > RGB Color.
8. In the Adjustment Layers Palette choose Solid Color.
9. Select a color from the Color Picker or from the Swatches Palette (which I prefer).
10. Your choice of color should be based on the tonal range you wish to see in your final B&W.
11. Go to your Layers Palette and change your Blending Mode to Multiply.
12. Because your Color Fill is on a Layer you may adjust the opacity to dial back the color to your desire.
13. In addition (IMPORTANT), you may add a Curves or Levels Adjustment to achieve the desired result.
14. Should you wish to change the color of your B&W "Duotone" simply double click the color fill and reselect.