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.
nappe nappie nape nappa nappy nap knap napa neap nope nippy nip knop neep nipa
nappe app ape yippie shoppe pappy chippie kappa chappie nappy taupe nappie zappy nappa rappee nape pope koppie gape gappy cape yippee shape cheapie chape tape rape sappy pappi buppie happy hippie jape pipe yuppie