since changing to osx i cannot for the life of me figure out how to print open windows on the desktop. this was an easy and handy thing to use in os9 but why has it changed now?
shift+apple+4 {select area with mouse} - after hitting the key-combo your cursor will change, just drag out a box and the area within it will be captured.
shift+apple+4+space - cursor will change to a camera, drag it over any window and it will take a capture of the selected entire window.
there isn't a "print window" feature under OS X. (not yet... ARE YOU LISTENING, APPLE!?) so you'll have to take a screen shot as described above and print it, which is ridiculous. (RIDICULOUS!! DO YOU HEAR ME, APPLE?!)