Sound modules?

How could I make my own sound modules like those in greeting cards and toys? And preferably easily, and cheaply.

I believe they use something called a 'Piezo Transducer' for a speaker. I could be wrong, both with the Idea and the spelling. to be able to record something, simply tear apart an old sound recorder, Record the sound, and then clip the wires on the Recording button, preferably removing it. finally, don't get a recorder with removable media (Tapes, Minidisks, etc.) it will be too bulky.