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.
spaes spas spays spies supes space sipes spews spues speiss spacey speise sepias spaz saps sops sips sups soaps spacy spice cepes spazz soups seeps sepoys specie spicey spouse hyssops suppose seapiece
spaes pas pes pawpaws rupees koppas cuppas pies nappas hopes buppies pupas ripes pews papas pehs japes chuppas toupees copies whoopees tapes cowpies tepas spews copays dopas pappies cowpeas chappies yippies lipase chippies wipes upas topees tawpies dupes spues spas capes repass space shoppes pipes sepias epees guppies hippies peso rapes napas loupes poppas nappies kappas opahs pias apace copes popes peps huppahs capias apes nappes kewpies pase pace jupes paps opes koppies lopes veepees pass gapes kapas hoopoes peas rappees paws coupes poppies pays hypes spays bypass pees nipas spies papaws dopes napes mopes cepes ropes puppies teepees repays topes sipes types weepies tapas whoopies chapes taupes cheapies chuppahs tepees shapes yipes supes yuppies
spae spa sipe spay spew spue supe