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.
greek creek grok creak grego creaky garigue cark cork grig grog kirk
creek reek greek reck reeky wreak wreck break eureka freak phreak creak dreck drek trek shriek
gree gore grew grey grue agree geekier ogre reeker reekier