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.
copies cowpies copes coupes cops cowpeas koppies coppice copious capes coops coups copse copays coypus capias coypous guppies kewpies caps cups kops capiz capos gapes goops kepis cuppas koppas
buppies nappies puppies cheapies guppies copies tawpies kewpies koppies weepies yuppies poppies pies yippies chippies chappies cowpies spies whoopies hippies pappies pes pis pice popsie peps hoopoes hypes lopes pips loupes apes kepis capes topes rapes ropes whoopees spues toupees sepias piss shoppes nappes rappees wipes cowpeas pias pews mopes ripes sipes pipes jupes topis types pees cepes spaes copes popes pehs peso pois peas napes tepees hopes epees tapis opes lapis teepees spews dopes topees capias taupes spice rupees japes coppice gapes tapes piso supes dupes tipis chapes veepees shapes yipes coupes
cop coop copay cope copy coup coupe cowpea cowpie coypou coypu scop scope