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.
speises speisses species sepses spices spouses specious supposes sepsis spaces spazzes spacious
peises speises peases pisses poises appeases capiases lapises sepses species speisses tapises
speise speiss sipes spaes specie spews spies spues supes aspis