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.
coopt coapt cooped copout cowpat caput coped capita capote copied copped couped kept
coop cop copay cope copy coup coupe cowpea cowpie coypou coypu goop goopy scoop scop scope