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.
spines supines spins spinnies spinneys sappiness soapiness soppiness sapiens spinose spinous spans spooneys sapience spoonies spawns speans spence spense spoons sapiency cioppinos
pines rapines chopines spines opines lupines repines supines pains pones openness lipins peonies lupins hyponeas deepness mopiness cheapness dippiness soppiness hypopneas hippiness tiepins pannes repins pepinos pipiness eupneas ropiness sapiens soapiness lippiness pawnees panes nappiness dopiness chopins peins weepiness ponies pinas peppiness papains spooneys dopeyness pians jeepneys lapins nippiness apneas spinneys penes loopiness happiness pions hippieness pins pinnies depones pippins hipness ripeness cioppinos sappiness spinnies spins peones pennies spoonies choppiness
spin spine spinney spinny spiny span spun supine