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.
speedo speed speedy sped siped spued spaed spied spado sapped souped soaped sipped sopped supped seeped spot spud sapid spate spite spout spade spode sapota sapote sippet sopite spotty zapped zipped zapateo
speedo peed beeped jeeped peeped seeped speed speedy wheeped cheeped
seep seepy sipe spae spew spue supe