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.
roast roost roust roset rest rust roseate rosette resit wrist rased wrest resat reest reset rusty rosed raised resite roosed roused russet reseat wriest wristy raucity risotto russety
boast oast roast coast toast roust host hasty nasty foist hast baste fast east boost taste sayst vast roost coset roset maist mayst most oust pasta pasty post joist tost wast wost yeast ghosty costa gast dost hoist bast past joust last vasty cast hosta doest beast feast haste cost ghost least posit lost mast moist moste caste ghast paste tasty toasty waist waste chaste yeasty
ras rais bros raise rase bras rays rias raws grassy proas crosse oars prose crass pross erose prosy erase dross brosy trass brassie roes roose cross brassy wrasse rows arose rouse rosy rousseau grass prase gross rose pros frass proso eros prossie eras roars brose drossy brass urase