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.
ripen ripieni ripieno rappen reopen repin rapine rapini repine repugn rappini
ripen pen shapen taipan spean ripieni peen pein peon happen gipon copen pean kippen lipin lippen loupen open rappen reopen keppen ripieno deepen cheapen shippen
ripe rip tripe rape rope ropey rupee cripe grip gripey gripe grippe grippy gripy drip drippy trip trippy