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.
spores sapors sprues spires spoors spares sopors sprees spireas sapours spurs spars spurries suppress spurreys saporous spiraeas sapphires speers sprays sparse cypres spiers spruce speirs supers spears cypress sappers sippers soapers suppers sparrows sporozoa spurious superrace sprucy
pores spores aperies roperies presa press pours pooris prees naperies repours perries poperies cooperies spoors cypress vapours sapours fopperies sopors apiaries spireas pries sprees spurreys suppress duperies pyres prese koupreys pareos cypres pareus preys parries peeress paries oppress repress moperies rapparees pares guipures sapors japeries sapphires vapors spares apres spires purees peeries peres sprues spurries depress topiaries
spore sparry supra spurrey spry sapour sopor spar spare sparrow sapor spire spiraea spirea spiry spoor spray spree sprue spur spurry osprey