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.
scar scary scaur scare scarry sowcar soucar scarey scry score sucre sacra scree saker screw sugar cigar scour saggar seggar soaker sacker sicker secure scoria square scurry sucker sagger screwy sugary saggier saguaro scoriae suckier siker skier skirr