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