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.
soapily sappily spail speil spiel spile spill spoil supply spale spall speel spell splay spool sepal supple
soapily pily choppily cheaply dopily sappily roupily ropily reapply peppily nippily loopily happily haply apply shapely ply