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.
sirup sirupy syrup syrupy sarape serape
sirup roup croup group larrup sirupy syrup syrupy drupe chirp chirpy chirrup chirrupy
sir sierra sieur sire siree sirra sirrah sirree soiree