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.
firs fairs fires fiars furs fairies froes vires fores frows frees feres faros fares viers vairs frass fries frays frise fears fours virus feuars fraise frowsy vireos ferias furies fierce frisee forays foresaw furioso ferrous foresee furrows ferries farrows furious faeries vars friz ferreous farcy force froze varas farci varus veers verse verso frizz farce furze furzy vrows
airs lairs chairs weirs deairs sirs pairs noirs mirs mairs kirs fairs keirs coirs heirs hairs vairs firs wairs whirs choirs