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.
cigar scar scaur sugar scary scare scarry saggar scarey scoria seggar soucar sowcar sugary cicoree saguaro scoriae suckier scry
cigar gar sugary seggar vigor agar beggar beggary eggar gaur vagary guar vicar jaggary jaguar cougar maigre megara rigor hegari muggar saggar sugar shikar