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