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.
sparky spark spriggy sprag sprig sprug superego
sparky park parka perky porky repark spark
spar spare sparrow sparry sprue supra spree spurrey spur spry spirea spray spiry spire spiraea spear spurry spore osprey