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.
capsid capacity coppiced gapeseed cuppiest gappiest
diapsid capsid biopsied gipsied gypsied lapsed depside diopside topside upside woopsed shipside
caps capes capias capiz capos cops copse cups gaps scapes scapose