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.
dopily duopoly deeply duple dapple deploy dipole topple
pily dopily loopily soapily peppily sappily roupily choppily nippily happily ropily ply poly replay apply ripply haply byplay uppile pile paly pial pail spail spiel pupil splay spill duopoly supply spoil play spile ripely ploy huipil reply hiply deeply speil pili pill reapply cheaply deploy shapely