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.
fallen villein flan felon flown feline felony valine valonia villain villainy
fallen sullen woollen mullen pollen glen woolen lean billon poleyn plena olein gallon leno lien alien baleen ballon pleon colleen xylene melena gallein galleon glean lallan mullein callan bouillon galena sileni clean relleno villein
fall fallow fully folly foal filly fillo fille fill felly felloe fellow fellah fella fell feal faille fail follow full valley