I've taken a list of English words, and examined each of them to see what they sound like (using the PHP metaphone function). This page lists the most common metaphone codes, along with their words. You can also search for a word of your own, and see which words sound similar - and which ones rhyme, and which ones alliterate.
coapt caput coopt capita capote copout cowpat kaput coped caped capped cooped copied copped couped kaputt kept
coapt apt opt caput coopt kaput leapt rapt wrapt teapot chapt
cap cop scop cape capo coop copay cope copy coupe coup cowpea cowpie coypou coypu okapi scape scope