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.
beastly bastile bastille biasedly biassedly bustle basidial biacetyl
beastly lastly ghastly vastly chestily moistly testily feistily justly fustily wrastle ghostly roseately hastily pastel hostly dustily mustily castle nastily gustily pastil lustily rustily mistily zestily coastal tastily mostly chastely costly yeastily
beast beastie bast best baste beset besot bestow boast