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.
casa cassia case caws cays cause causey kas gas cos quassia goas kays gaes kaes cosy cows coos gays cuss keas cues coss kaas koas coys gawsy quass quasi quais cosie gauss gassy cusso cosey quays