A while ago I wrote some kind of an introduction to the use of blending modes on black and white layers in photoshop (
link) (if you haven't worked with adjustment layers or blending modes before you should probably check it out before starting on this one)
Now I thought I would give an actual tutorial on one way blending modes can be used and also on how adding a tint can give really cool effects. This is the result we'll be going for:
We will be starting out with this image

(you may use it to try out this tutorial to easier see what changes each layer actually does, but don't use it for anything else, please!)
For those of you with CS2 or earlier I will write the steps inside two of these (()). You'll get more or less exactly the same result but in a little bit different way.
1. We will be starting with adjusting the levels. At first I thought about only adding the version where the levels were already adjusted but I thought that by including this step it's easier later to see why I made the picture lighter in the first place.
- Make a new levels adjustment layer.
- In the window that pops up, write 6 in the box to the left, 1,54 in the middle one and leave the right one as it is.
2. We will now be darkening the image a bit again. And this is where you might ask why I even lightened it in the first place. Try "removing" both layers (click the eye so the effects aren't visible anymore) and see the difference after finishing this step.
- Make a black and white adjustment layer ((or channel mixer if you have CS2 or earlier)).
- Click the auto button and then ok ((check to monochrome and then click ok))
- Change the blending mode to multiply.
- Set the opacity to 50%
3. Now we will get some more contrast here.
- Copy your b&w layer by clicking ctrl+J
- Change the blending mode from multiply to soft light.
4. Now we are going to start to get some cool effects here.
- Add a new b&w layer. ((add a hue and saturation adjustment layer))
- At the preset, in the drop down menu at the top, select the yellow filter. ((jump over this one))
- Check the tint button at the bottom of the b&w box options. ((check the colorize box))
- Set the hue to 190 and the saturation to 20 and click OK.
- Set the blending mode to overlay.
5. This last step makes the picture a little bit darker again.
- Copy the layer from step 4 by marking it and pressing ctrl+J
- Change the blending mode to multiply
- Change the opacity to 20%
Try to hide and unhide some of the different layers to see how they all affects each other.
Hope this has been of any help