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.
reapply reply rappel replay ripply repel repeal replow repoll ripely ripple ropily roupily
reapply apply choppily dapple supply soapily sappily ripply rappel peppily nippily happily haply apple appel appal cheaply shapely ply
reap repp rappee frappe crappie crappy grappa preppie preppy rap rep