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.
prepay preppy prep preop preppie perp prop hyperopia priapi pyrope hyperope
prepay repay arepa forepaw creepy crepey crepy preppy sherpa
pare pree repro repair reaper pareu pere perea pereia pore pareo pure prey puree pyre peeper pepper peppery peppier reappear repour spree