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.
goodness gaudiness goutiness godowns codeines codens codons kidneys guidons cottons codeins ketones codeinas cuteness guidance cattiness quietness coetaneous cotans
voidness goodness badness deadness sadness redness madness oddness lewdness loudness soddenness readiness hiddenness moodiness dowdiness knottiness rudeness matiness iodines fitness mootness dottiness giddiness dunness seediness haughtiness gaudiness fattiness doughtiness tidiness shadiness woodiness wittiness wideness whatness weediness ruddiness ruttiness kidneys tattiness nuttiness beadiness denes neediness muddiness rowdiness patness liteness meatiness dueness nudeness pettiness dunes lateness dynes bawdiness mateyness dines pottiness meetness cattiness hotness goutiness muteness neatness sootiness fatness suddenness nattiness cuteness leadenness reediness quietness rootiness rottenness jettiness bittiness battiness tautness headiness titaness wetness whiteness witness woodenness chattiness shoddiness