There are many ways to convert an image to black and white.
Here are some.
1) If shooting in raw mode just move the saturation slider all the way to the left in the raw plug in window. You can then go into the calibrate tab and adjust the sliders to your taste.
2) Go to the image menu - adjustments - desaturate.
(note: i have typically used this method and then just applied a curve)
3) Go to image menu - adjustments - channel mixer. Click on the monotone check box and then start to play with the sliders.
4) Go to layer menu - new adjustment layer - hue/saturation.
Move the saturation slider all the way to the left.
Go to layer menu - new adjustment layer - hue/saturation and create a second adj. layer.
Hit ok when the box pops up.
Drag this layer under the first hue/sat layer in the layers palette.
Change blend mode to color (second hue/sat layer only).
Now double click on this layer and play with the hue and saturation sliders.
I also added a curve adjustment layer to the top of the layer stack and bumped up the contrast a bit.
I just applied this method to 10 wedding reprints and it worked great.
My settings were hue -32, sat +2.
I did need the curve for contrast.