Do you want to know the hard way, or the easy way? I'll start with the hard way since that is how I first did it, and took pics for every step. :) The first thing is to take a profile pic. All you need is a blank background. If you are doing more than one, make sure you are the same distance apart from each subject. About 4 feet away is what I did. Then print out the pic. You can use fast draft to save on ink, but I would use card stock paper.
I cropped each photo to a 5x7 crop so they would all be the same size. I think if I was to do this again I will use an 8x10 b/c the actual silhouette is smaller than a 5x7.
Now just cut around the person with a craft knife.
Trace the pic. onto black cardstock. If you want your finished silhouette to be facing the right, then trace it facing the left. This way you won't see any stray pencil lines and the cut is much cleaner on the opposite side. When this one is finished she will be facing the right side.
Cut out one more time. Pay close attention to details, especially around mouth and nose. Make sure things are rounded and not pointy.
Choose a contrasting background. I used scrapbook paper and cut it to an 8x10. Then I printed their names on it and my signature.
I used a glue stick to apply the silhouette to the background and framed it. That's it. I think they look pretty good. Now do you want to know an easier way? This idea didn't even hit me until after I had done all 4 of them the other way. Oh, well.
If you have photoshop or something similar. Then you can just take your profile pic. and use the lasso tool to trace around the person. Now I'm not great with the lasso tool and I didn't get the exact cut I was wanting, but with some practice, I bet it can be done a lot smoother.
After you have traced the image, go up to edit and select fill layer with black. Then cut and paste onto a solid colored layer. That was much easier huh? I did a real quick one on the computer to just see if it can be done. Like I said there are some rough edges, but this could totally be done. Here are the ones I did on the pc.