This is how I did it on my iBook about a year ago. However, you must be VERY careful with this method... it could screw up your system severely if not done correctly! For that reason, I recommend not doing this method if you're uncomfortable with the possible outcomes from the mistakes and waiting until someone posts an alternative way. However, if you ARE comfortable...
Open up the Terminal.
Type in the following:
cd /
sudo rm -rf "System Folder"
Exactly like that, quotes and everything. You will be prompted for a password after entering the last line.
This deletes everything, without question, from "System Folder" which is your Mac OS 9 folder. Making a slight mistake and entering rm -rf "System" will delete your entire OS X system folder! So once again, I advise being extremely careful with this method, and finding an alternative if you are uncomfortable with it.