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.
spiced spaced spoused sappiest seepiest soapiest soppiest soupiest supposed sapphist zappiest zippiest
spiced coppiced paced peaced peised pieced poised biopsied gipsied gypsied spaced
spicey spice spicy sepias space spacey spacy specie speise speiss spies aspis espies