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.
sport sporty support seaport sprat spurt sprit spirt spirit sprout spored sprite sporoid spoored separate suppurate superette spared sparid spread spired sparoid sparred speared speered speired spiered spiroid spurred supered superadd superroad
port support rapport aport deport sport seaport report sporty spurt sprat pert spirt apart prat part depart sprit
spore sparry supra spurrey spry sapour sopor spar spare sparrow sapor spire spiraea spirea spiry spoor spray spree sprue spur spurry osprey