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.
green greeny greenie careen grin gran grain grown garni grana groin groan groyne garron granny gurney grainy coreign grannie guarana guarani carn corn curn karn kern kirn
boreen careen treen preen moreen green terreen tureen rein pereon greeny siren warren hereon serein terrene whereon barren arene herein bren murein wherein frena serene pyrene arena wren gyrene syren chirren
gree gore grew grey grue agree geekier ogre reeker reekier