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.
spireas spiraeas spires sprees sprues spores spiers sprays spears spares speirs sapphires spurries suppress spars spurs spurreys spoors spruce sapors sparse speers cypres supers sopors cypress sappers sapours sippers suppers soapers saporous sparrows sporozoa spurious superrace sprucy
spireas capoeiras sapphires spiraeas spires
spire spirea spare speir spier spiraea spiry spore spree sprue aspire osprey