Cans of compressed air are perfect for blowing away the junk that gets under the keyboard.
As for cleaning the iBook itself, I recommend a soft, moist cloth. Try to avoid dropping water on the iBook as water and electronics generally don't mix very well. I'm not sure what could be causing your click problems, but taking it apart yourself would void the warranty. Have a professional do it if it's really bad.
For cleaning the screen, again use a soft, damp cloth (no chemicals/Windex/etc).
www.klearscreen.com is also a great choice.