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.
splake soaplike souplike ziplock
splake cuplike tapelike plack pollack apelike hiplike hooplike pealike maplike liplike pipelike popelike puppylike ropelike soaplike souplike whiplike
splay sepal spail spale spall spell spile spill