iBooks were introduced in 1999.
Look here for more information about the iBook line.
Does it say iBook G3 or iBook G4 on the bottom of the display border?
To find out what Mac you have, do this in Mac OS
and to find out what Mac OS version you have, do this
(or expand the Software Overview selection in System Profiler)
or do this in Mac OS X
The yellow 2 will tell you what Mac OS X version you have and the red 3 will tell you what Mac you have.
After that more can be done.