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.
staple steeple stipple stipule stopple stapelia stipel steeply
staple dapple diploe dipole duple tipple topple steeple stipple stipule stopple tadpole woodpile
step steppe stipe stop stope stupa stupe