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.
deepness deepens depones dopiness dippiness dopeyness teopans tiepins doupionis douppionis
hipness deepness cheapness jeepneys sappiness penes nippiness opines peppiness ripeness soppiness weepiness pones supines eupneas spines depones dopeyness chopines apneas pines rapines repines hypopneas pipiness loopiness lupines mopiness nappiness hippieness soapiness hippiness lippiness ropiness happiness dippiness dopiness openness panes choppiness