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.
papacy papas papaws pawpaws paps popsy pappus papoose pappies pappose pappous pappoose
papacy pacy spacy pace pacey pays apace copays repays space spacey spays spicy
papa papaw pap pappi pappy pawpaw