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.
quieter quitter quoter quittor kiter cuter couter cutter guider gutter goiter gaiter guitar gaudier guttery cautery guttier goutier gater cater cooter cuatro cotter coater kidder quatre cattery cattier coterie cottier gaudery
quieter dieter getter pewter biter gaiter eater feater bitter netter peter niter better meter baiter meeter rioter writer litter seater lieder sitter kiter deter teeter titer waiter whetter whitter chitter quitter knitter hitter ritter jitter heater vetter hetero neater nitery neuter petter miter retear meteor vetoer loiter liter citer letter setter goiter suiter fetter fitter beater tetter titter wetter whiter cheater sheeter