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