Apparently Apple introduced a little bug with 10.3.2 where the boot script doesn't find a file where it's supposed to be. You can fix that by typing the following command into the Terminal (one long line, broken with a backslash here for narrower display -- if it doesn't work, remove the backslash and type as one long line):
sudo cp -p /System/Library/Extensions/BootCache.kext/\
Contents/Resources/BootCacheControl /usr/sbin
Enter your password and then reboot twice. Et voilĖ. This information appeared first in the Appple Support Forums.
[robg adds: I haven't tested this one, though I will the next time I hit the restart keys!]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20031227084312338