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.
merces mercies merises murices marses merisis morasses morrises mirzas
farces terces merces forces coerces pierces tierces sources parses bourses arses graces braces furzes erses courses prices hearses varices carices marses curacies precess process cercis farcies orrices truces gorses birses boraces rices hyraces burses verses curses races terraces recess mercies corses horses traces carses nurses cruces murices piracies purses torses trices perses worses
mercy meres morceau amerce emeries omers