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.
siren syren serein serene sierran sorn sciurine saran sarin serin serine saurian serrano
siren bren kirn cairn careen girn iron giron herein frena terreen hereon boreen treen serein tureen preen wherein pereon chirren moreen firn rein arene murein mirin cairny green airn arena gyrene bairn barren wren terrene syren triene serene warren pyrene whereon pirn shairn
sire siree sir cire saree sere sierra sieur sirra sirrah sirree soiree sore sure osier sizer