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.
harden hearten hordein harridan hirudin
burden harden garden warden hordein chorten torten cordon trodden joyridden pardon jordan lurdan hearten cardon guerdon broaden bourdon ridden redeny redden lardon verdin marten shorten
hard hardy hairdo haired hared harried hart hayride heard heart hearty herd hoard horde