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.
supra super spray spirea supper spry spiraea spur soupier spar spire spoor spier spiry sapor speer spree spear spore sprue speir sopor spare sapour sapper soaper sipper sparry spurry sappier seepier soapier soppier sparrow spurrey sapphire
supra para prao prau pray proa coppra copra coprah opera pauper spray super duper whipray yauper