Step 1: Gather the materials
The 6.4Mohm resistor should probably be changed depending on your photoresistor. Choose a resistor about halfway between the usual light and dark values of your photoresistor.
*5" x 2.5" x 2" project box with metal insert. (like from radio shack)
*9V battery clip
* a radioshack piezolectric buzzer (no internal oscilator)
* 1x3 and 1x6 bits of pin header (http://en.wikipedia.org/wiki/Pin_header)
* 9V battery
* photoresistor (from radio shack, came in a variety pack)
* single pole double throw bat style switch (used and single pole single throw) (as in picture)
* resistors: 112ohm, 6.4Mohm.
* diode (1N4002) (may substitute some other power diode)
* stranded wire
* shrink tubing for just-in-case insulation since the parts are just freely connected.
* 2 sets of #2 machine screw and nut. 1/2" long.
* soldering iron and solder
* drill and assorted bits
* super glue
* a bit of pillow stuffing or something.
Step 2: The Wiring
You should be able to solder wire to wire when needed, and on parts that will be close (such as the leads coming out of the photoresistor) cover them with shrink tubing after soldering.
!!Remember to thread the shrink tubing on before closing off that part of the circuit!!
You will want to give extra wire to the photoresistor since it needs to be mounted in the top of the case and will want a little extra room to work with.