Here's another fun project from Photojojo. In this tutorial, they show you how to make a color image from three black and white photos using channels.
In Photoshop, you'll switch your Layers palette over to Channels and work there. Select and copy a different channel from each of your three photos and paste them into a new image. You can play with the channels until you find the look you're going for in your finished image.
I really think you're going to love this little experiment! I tried not to go overboard like I usually do with new techniques. So, I only made three of these images... so far. EDIT: Now, I'm up to five. :)