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.
warren warn wherein whereon worn
barren warren chirren arena hereon whereon frena siren serene pyrene perron murein marron green garron curran careen gyrene herein wren rein arene boreen wherein treen bren tureen terrene syren serein sierran preen pereon moreen terreen
war wair ware wary waur wear weary wirra worry aware sware