Here it is. There is a mouse, a rodent, and a mouse, a thing you direct the arrow with on your computer. Plural for a mouse, the rodent, would be mice. I know that 'cause I'm book learned. But what is the plural for mouse, the computer thingy? If you have four of them, would you refer to them as mice�mouses? I've asked a few people in the know, and they don't know.
-- Lucious Periwinkle, Normal Heights
Sometimes a little book larnin' just gives you a headache, Lucious. Grandma is applying compresses to the elves' overheated domes even as we speak. They say, "Use either one! Use either one! Who cares? Go away and leave us alone!" They couldn't find any general agreement at all. Some conflicting trends, but no straight answer. Linguists and the press and anyone who deals with words for a living have from the beginning been in favor of "mice." Mice is the plural of mouse, and that's that. Doesn't matter whether we're talking about a field mouse or a computer mouse, and the answer is so obvious the word squads can't imagine why we would even bother to ask.
There was a time, early on, when techies snickered if you called more than one mouse "mice." Mouses was the preferred word for those in the know and still is for some. Maybe it's the nagging from their editors, but lately many tech dictionaries give "mice" as the preferred choice but hedge their bets by saying either one is correct. Any Internet search of device sellers will show that both are in use. Microsoft has always advised their employees to avoid the issue completely by referring to "mouse devices." A typically crafty solution.
Independent thinkers from both sides of the fence argue that "mouse" is no different from, say "Walkman," the portable radio. The plural of Walkman isn't Walkmen, so why should the plural of a computer mouse have to be "mice"? If somebody pinches your butt, then pinches it again, that's gooses, not geese. But the elves suggest you might want to throw in a third possibility, the always popular "meeses."