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.
colugo colog glug clog clag colloquy collogue cluck colic colleague colloquia calque galago cloggy claque cloque cliquy clique cliquey coeliac colicky cowlick
colugo lug logo beluga vulgo galago glug plug slug
col collie coyly coulee cooly coolly coolie cool coly colly cole clue cola coil coaly coala coal cowl coquille