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.
whirs whirrs weirs wairs wires whirries wheres whores whereas wars wherries wares wears worse warsaw wooers wearies worries
whirs fires nairas lairs liars kirs piers noirs sires coirs keirs hires tahrs zaires tires hairs wairs iris virus whirrs heirs wires viers chars vairs chirrs vires choirs liras shires mirs shris mbiras airs fiars giros mires nairus lehrs liers quires cires pairs sirs guiros kiers ires tiers deairs tiros biros biers weirs birrs firs hers chairs buhrs chiros fairs chirus birse shiers mairs shirrs moires yirrs
whir whirr whirry wair weir where wherry whore wire wirra wiry