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.
sapor sapour spore sopor spoor sapper soaper spar sappier spry soapier spur sapphire spree super speir sprue spiry spire spier speer spare spear sipper sparry spurry supper zapper seepier soppier soupier sparrow spurrey zappier
vapor sapor cheaper taper diaper spoor soaper japer repour reaper raper paper leaper gaper poor caper heaper vapour vapory aper pour pore sapour sopor spore diapir tapir shaper