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.
couples cupules copals cupels capless copulas cupolas gapless keypals
couples applies huipiles hapless fipples hipless reapplies soapless ripples spales papules popples nipples supples zeppoles maypoles dapples lipless dipoles peles tipples cupules topples hopples wheeples hoopless apples pales supplies pleas capless plies poles plews replies soupless sapless spiles peoples pupils pules nopales zipless napless diploes maples tipless cupels topless gapless uppiles piles shipless
couple copal copula copulae cupel cupola cupula cupulae cupule