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.
spinous spinose spins spines supines sapiens spans spinnies spinneys cioppinos soapiness sappiness soppiness spawns spense spoons speans sapience sapiency spooneys spoonies spence
spinous pianos epinaos pepinos ripienos cioppinos spinose
spin spine spinney spinny spiny supine