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.
spacer spacier spicer spicery spicier supposer
pacer spacer pacier piecer appeaser spacier spicer spicery spicier
space spacey spacy spaes spas spays spaz spazz specie spice spicey spicy