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