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.
speel speil spell spiel spool spoil splay spill spile spall spale spail sepal supple supply sappily soapily
peel speel chapel peal pele appeal appel cupel lapel repeal rappel repel ripely speil spell spiel tupelo shapely
seep seepy sipe spae spew spue supe