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.
sprays spireas spurs spars spurreys spiraeas sprees speers sopors sprucy speirs spares sprues sparse spores spears supers spiers spires sapors spoors soapers sippers sapours suppers sappers saporous spurries sparrows sporozoa spurious suppress sapphires superrace cypres cyprus spruce cypress
prays sprays whiprays piracy copperas spurreys operas biopiracy spireas koupreys coprahs coppras copperahs praos capoeiras aporias copras paras proas preys praus prase apyrase
spray spirea supra spurrey spur spry sprue spree spore spiry spire spar spiraea spear sparry sparrow spare spurry osprey