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.
reopens repins ripens repines ripeness ripienos ropiness rapines
opens reopens copens pens sapiens chopins ripens teopans lippens spense speans peins happens penes peens peans deepens peons cheapens penis shippens