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.
spiral spirally sporal sprawl spirula sprawly spirilla spirulae spryly superreal superalloy sparely sporule superlay superlie
spiral parral caporal papyral puparial sporal sprawl superreal chaparral
spiraea spiry spire spirea sprue aspire spree spurry spray spur spry sparrow spore sparry spare spar spurrey spier supra speir osprey