If I plug in my mouse while the iBook is sleeping (lid closed) when I wake it my screen comes up for a few seconds and then goes dead. Nothing will wake it, except a complete cold reboot. Also my freshly charged battery went totally flat. This happened twice with 2 different batteries before I realized what was happening. The same crash occurs with the power plugged in except the battery appears unaffected (as expected). I am posting this to Apple but thought I should warn everyone as it can stop you dead if power isn't handy.
Mike
Mac OS X Hints
http://hints.macworld.com/article.php?story=2001032822260350