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.
shittah shitty shit shott chetah chitty cheetah chit shut shad shot shat sheet shied chott shade shoat shoot shote shout shady shute chaeta chatty shadow chaetae chateau chuddah shadowy