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.
sparse spars spares spears spurs sparrows spires sapors spruce spoors speirs spiers sprees supers sopors sprays speers spores sprues sapours suppers sappers spireas sippers soapers saporous spurious spurreys spurries spiraeas suppress sapphires superrace sprucy zappers zippers sporozoa
parse sparse spares pars spars repursue repairs reappears parrs apprise leprose appears purse paras pares paris spears uprise vaporise pears reprise prose perse porose praise prase prese prise peruse pursue appraise apyrase coappears operose reappraise pairs upraise uprose
spar spare sparrow sparry sprue supra spree spurrey spur spry spirea spray spiry spire spiraea spear spurry spore osprey