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.
lippen lipin loupen lapin lupin lupine
happen keppen shippen kippen lippen rappen pen peon pean pippin cheapen copen spean open loupen reopen ripen deepen pein shapen peen shippon
lippy lip lipa lipe loppy blip flip flippy clip slip slipe slippy