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.
sullenness soleness silliness slyness sallowness slowness silenus xylenes silence silanes salines salience selenous selenious salons solans solons salinas saloons solanos solions saliency zillions
alienness sullenness leanness blennies blueness vileness haleness juliennes cleanness glueyness maleness paleness plainness soleness wholeness