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.
deepest deposit dopiest dippiest typeset typiest tippiest typist deposed depside diapsid
deepest pest zappiest soupiest zippiest gappiest goopiest quippiest loopiest soapiest cuppiest lippiest nippiest repast ropiest sappiest dippiest tippiest typiest whippiest chippiest mopiest peppiest hippest ripest heppest happiest epeeist pesty loppiest nappiest pesto hippiest roupiest pipiest seepiest soppiest pappiest hoppiest dopiest typeset weepiest cheapest choppiest pst