Leave the iBook unplugged, battery out, for a few hours to make sure everything dries. If the solvents didn't get to the trackpad, it's probably just got a Windex puddle stuck on the edge.
At least the iBook doesn't need an extension to get the trackpad working properly, like my Powerbook 1400 does.
is it running OS 9 or OS X? If you don't mind using iCab and slightly older software, you might get better performance by dual-booting OS 9.2.
