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.
sin sine sign sinh sain sinew scion seine sinewy son sen sun sienna syn zin cion sewn zein sene zine snow sown soon snaw sawn seen sone syne cine sane sunn senna sauna scene sonny hyson scena sunny sunna snowy sawney sunnah zinnia