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.
spored spoored spread spared spired speired speered spiered supered sporoid sparred speared spurred sport sporty sparid sprite seaport spiroid sparoid support zippered superadd separate spurt sprit sprat spirt superette superroad suppurate spirit sprout
vapored spored spoored pored peppered supered preed reappeared appeared purred coappeared coppered pureed spread chippered diapered lipread leporid repoured sparred speered spiered kippered pried papered capered vapoured copyread paupered spurred lippered peered loppered parred pared paired coopered tapered parried zippered poured lappered rapiered repaired spared speared speired spired choppered
spore sparry supra spurrey spry sapour sopor spar spare sparrow sapor spire spiraea spirea spiry spoor spray spree sprue spur spurry osprey