One thing that was driving me crazy was I had this smell coming from my dual USB iBook keyboard that would not go away. No matter how much I cleaned it and how many natural and unnatural substances I cleaned it with, it would not come out. Via a link at MAC POWERPC came my answer. MAC POWERPC wrote a piece about The iBook Guy, so I went over to his website and saw this little article titled, "Why does my iBook G3 smell bad?" Putting on my Sherlock Holmes hat and using my amazing skills at deductibility, I followed said link.
Long story short, the odor isn't from any germs or anything. It's from the glue underneath the keyboard apparently decomposing. Other than removing the glue, the only solution is to keep the laptop open when not in use. Or maybe wave it through a cloud of perfume, but that's probably more expensive than the iBook's worth;)