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.
speil speel spail spell spiel spile spill spoil sappily soapily sepal spale spall splay spool supple supply
speil appeal ropily repel peppily rappel lapel cupel loopily happily huipil appel spill spiel dopily peal uppile spail choppily sappily pily pail pial soapily roupily ripely pupil repeal peel pele nippily pill pile pili spoil spile tupelo spell chapel speel shapely
sepia sipe spae spew spue supe