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.
takeup teacup toecap
makeup takeup shakeup kep wikiup keep kepi backup fuckup hookup kickup lookup mockup pickup skep wickiup lockup checkup cockup
take tack tackey tacky taka teak tike toke tyke stake