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.
speered speired supered spiered speared spored spread spired spared spurred sparred spoored zippered superadd superroad superette sparid sparoid sporoid spiroid spirt sport sprat spurt sprit spirit sporty sprite sprout seaport support
peered speered chippered diapered supered speired capered coappeared coopered coppered kippered lappered appeared loppered papered paupered peppered rapiered reappeared speared lippered spiered zippered tapered choppered
speer spear speir spier spree super asper