A quick search and I find there's a guy on ebay who sells
iBook keys of your choice. $2.85 US per key, plus shipping I'd assume.
But really, many keys on my keyboard look like that. Doesn't really affect anything personally. I once took out all the keys of my keyboard to clean all the dust and junk that gets stuck under them, and at first I started putting them back in order, but it was taking too long and I never look at the keyboard anyway so I just decided to put them anywhere to save time. Didn't make a difference...at least to me. Many other people who ever happen to use my computer now have some trouble with it

. Maybe I should just buy
one of these next time.