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.
cape cap gape capo cope coupe cowpea cowpie cop gap cup copy kapa gapy coup coop gawp copay coypu cuppa cuppy gappy kappa
ape jape cape gape nape rape tape chape shape pe