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.
cowpeas cowpies copes copays copies coupes cops copse coups coops capes cuppas coypus koppas capias copious koppies coppice kewpies coypous caps cups kops capos gapes gawps goops kapas kappas guppies
cowpeas peas pease appease cowpies kewpies pawpaws tawpies wipes chapeaus pas pes
cowpea cope coupe cowpie scope cop