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.
spins spines sapiens supines spinose spinous spans spinneys spinnies spoons spawns speans spense sappiness soppiness soapiness sapience sapiency spooneys spoonies cioppinos spence
pins lupins lipins spins pippins lapins chopins tiepins repins pinas taipans pians deepens teopans pains pines papains jupons gipons sapiens peins pepinos coupons pons weapons shippens yapons supines youpons reopens pens capons spines japans puns cioppinos rapines lupines pans repines opens pions copens chopines lippens ripens kneepans happens spans cheapens shippons yaupons opines yupons
spin spine spinney spinny spiny span spun supine