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.
herpes harpies harps hairpiece
herpes pyropes reps crops gorps cripes preps perps drips rapes crappies corps sirups sarapes dorps rappees rips tripes creepies raps sharps drupes carps tarps ripes trapes chirrups liriopes grips tropes gripes turps groupies warps corpus ropes props rupees harpies syrups rewraps serapes carpus crapes drapes traps hyperopes preppies crepes croupes croppies frappes bewraps craps wraps grippes corpse urps gropes troupes grapes trips larrups fraps chirps towropes burps hydrops harps drops sharpies sherpas