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.
seis seise sis sews sues seas sees sissy seize seesaw xis cis sos sows sass suss saws cess soys sizy says sous sice syce size cease cissy saice sassy sauce souse sycee