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.
spurrey spurry sparry spur spry spore sprue spire spare spray spiry spree sapour spirea spiraea sparrow spar sapphire spoor speir super speer spier sapor spear sopor supra soaper sapper supper sipper sappier seepier soapier soppier soupier