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.
species speises specious speisses spaces spices seapieces spacious sepses sepsis spazzes spouses supposes
species peaces peises pieces poesies kneepieces papacies seapieces speises toepieces showpieces