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.
haply happily hiply hoopla hopple huipil
haply cheaply ply hiply poly play pily paly pally papal ploy chapel ropily sappily splay deeply dopily choppily peppily ripely replay soapily roupily byplay happily duopoly deploy supply ripply reapply apply lapel reply papally nippily maple loopily shapely