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.
wideness widens whiteness wetness witness woodenness weediness wittiness woodiness whitens witneys whatness witans wheatens
dueness wideness cuteness lateness rudeness liteness muteness whiteness nudeness reediness voidness bawdiness soddenness retenes lewdness rowdiness knottiness rootiness fattiness nattiness patness goodness moodiness meetness sadness quietness muddiness ruddiness seediness neotenies shadiness woodiness wittiness mateyness whatness weediness tidiness tattiness doughtiness deadness neatness suddenness readiness rottenness madness oddness pottiness pettiness goutiness butenes redness bittiness dienes meatiness gaudiness neediness cattiness haughtiness matiness ruttiness hotness nuttiness giddiness beadiness battiness tenues sootiness fatness badness redenies wetness codeines jettiness mootness headiness denes dunness hiddenness denies leadenness ketenes dottiness fitness dowdiness tautness titaness loudness witness woodenness chattiness shoddiness