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.
stoup stop setup situp stoop stope stowp stupa stupe step steep stipe steppe
stoup tup top biotope stupe stop stowp tope topi topo atop atopy getup letup metope netop setup situp stoop stope cutup stupa tittup
stoa stoae stoai stow soused toused