This is the method that I usually use for black and white images. I find that most actions have a tendency to blow highlights. This method is very straightforward and allows you to protect your own highlights.
1. Open your image in PS.
2. Duplicate the background layer. Rename it 'bw'.
3. Image > Adjustments > Gradient Map. Make sure that the gradient selected is the black------white gradient. Click ok.
4. Duplicate the bw layer. Rename it 'curves'. Alternatively, do the next steps on an adjustment layer.
5. Image > Adjustments > Curves.
6. Look at the graph in the curves dialogue. By changing the shape of the diagonal line, you can 're-map' the pixels in your image. You can make shadow, midtone and highlight pixels either darker or lighter, simply by placing a box on the appropriate part of the line and moving it. The bottom left area of the graph represents the shadows, the top right of the graph represents the highlights and the rest is all the pixels in between (the middle area obviously representing the midtones).
7. By far the most common criticism of bw conversions is that it looks 'flat' or 'grey'. This tends to be because the image lacks contrast and the midtones are too dark. Place your cursor on the box in the bottom left corner of the graph. Pull it to the right, making it sure it remains on the bottom axis. This remaps the dark pixels, making them slightly darker. Don't overdo it! Then place your cursor on the box in the top right corner and move this part of the graph to the left, keeping it on the top axis. This makes your light pixels lighter. These two steps together (lightening lights and darkening darks) add contrast to an image.
8. Next, place your cursor in the middle of the line and drag it upwards. This brightens your midtones.
9. Now, in remapping the dark and light portions of your image, you may well have clipped shadows and highlights. Look closely at the image and identify these areas.
10. Click on the rectangle with a circle inside, in the layers palette, to add a mask to the curves layer. Paint on the mask with black wherever an area has been clipped.
Final conversion: