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.
spiroid sporoid sparoid sparid spired spirit speired spiered spirt superroad spread spored sprout spared spoored speered spurred sparred speared supered superadd sport sprat sprit spurt sporty sprite seaport support
speir spier spiraea spire spirea spiry aspire