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.
sassy sass sissy seas suss says saws cissy saucy zas sis sos seis sews sizy sous sows soys sues cess syce sees
gassy massy sassy bassy ass sass wrasse passe mussy missy easy assay queasy messy fussy bioassay lasso lass quass gussy sissy tass wussy gawsy missay masse essay bassi hissy lassi hussy lossy gauss bossy bass massa mass mossy pass pussy cissy kissy basso daisy tasse chasse
sass sassy ass massa tasse mass dassie lasso sissy lassie says lassi lass passee pass masse cassia massy bassy basso bassi bass assay gassy assai passe saws seas suss tass tassie