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.
fart frat fort fret frit fard forte forty fruit farad fared fritt fruity faired feared ferity ferret forrit fretty ferrite variate faraday variety ferrate ferrety ford vert fiord fired fordo fraud freed fried vertu virtu
art boart fart hart heart cart kart quart mart part peart dart tart wart chart