lighting to create a silhouette?

[rikkersc]

How do I set up lighting in order to create a silhouette of a person? I want the silhouette to be crisp, not blurred like a shadow.
I am not sure how to achieve this.
I could go one of two ways -- an actual silhouette projected onto something or just setting the lighting so the person comes out "shadowed". I don't want to be able to see facial features or clothing patterns or colors anything of the sort.
I am planning on creating a series of these pictures that will be blown up quite large (at least poster size) and hung on a wall.
I need them to have sharp outlines, but I am not sure how to achieve this total effect. Any help is appreciated.

[Nai no Kami]

You should have your subjects backlit and with a really strong light. Moreover, you should try to underexpose the photo a bit. The results will depend on the camera you are using. Try using different exposure levels. It is posible, however, that you still get some details on the subjects (for example if some of the back light bounces to them or because another source of light; should that be the case, a little brightness/contrast fiddling surely will solve it.
A very useful setup is to shoot your subject at midday and against a very white wall while your subject is in the shade. Here is an example I did (if you notice the glass, you will notice that this photo is not B&W).

http://i12.photobucket.com/albums/a213/nai_no_kami/IMG_1050.jpg

[thingy]

As Nai no Kami says, backlighting your subject is the best way. Assuming you are using a DSLR (as I dont know which point and shoot cameras allow this), make sure you take your meter reading from the light/sky/wall/whatever to the side of your subject. This can be achieved by selecting spot metering then pressing the shutter release half way whilst pointing to the side of the subject. You then need to lock that meter reading using the AEL feature of your camera (unless your using Manual mode in which case you just have to adjust your settings till you show a correct exposure). Recompose your photo taking your focus from the edge of your subject and shoot away.

Works for me anyway :)

G

[rikkersc]

Thanks. These are both very helpful ideas. The photo that is posted is very similar to the effect I am trying to achieve. :)

[mdwsta4]

simply expose for the brighter background. BAM! you have a silhouette.