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.
sopors spoors sapors spores soapers sapours spurs spars saporous sprues sprays spears spiers spares sprees spires sparse speers supers speirs sappers suppers spireas sippers spurries sporozoa suppress spurreys spiraeas sapphires spruce sprucy zappers zippers sparrows spurious
vapors sapors sopors sapours kippers knappers capris rippers copers gippers keepers leapers capers cuppers lappers pars cyprus loppers wrappers coppras loopers pores mopers pros pours nippers pooris spoors purs uppers yaupers shoppers topers shapers chippers tapers wipers whoopers japers whappers poppers gawpers rappers spurs tappers repours dopers peppers zippers diapirs hopers suppers sippers apres lepers sappers zappers papers spores tapirs vipers dippers whippers moppers toppers shippers ropers hoppers paupers vapours lopers heapers nappers gapers mappers pipers copras cypres repros gyppers cheepers cappers soapers hoopers rapers boppers reapers beepers jeepers coppers coopers lippers quippers yappers apers hypers peepers spars supers diapers dupers tippers weepers whoppers choppers yawpers
sopor sapor sapour soaper soapier soppier soupier spoor spore