if you have the dev tools, the plist editor will do this for you. otherwise, just open the plist up in some text editor, and slog through the XML.
If that isn't your bag, bust out a terminal and type:
defaults read com.apple.dock
to see what's in the plist, and then you can apply the many dock hacks with
defaults write com.apple.dock xxxxx
where xxxx is the particular hack.