1st, I assume you read my Linux (install?) guide for PowerPC MAC, then, go to the 2nd point. If not, 
click there. http://bitbin.it/HGvpskkn . Basically, you should follow Linux Mint install instructions at the link.

2nd If you have read my application list guide suggested dependening on the 
CPU (G3, G5), skip this point too, if not http://bitbin.it/HGvpskkn

3rd Let's go optimizing. Connect your Linux based MAC to an internet connection. Next, open a terminal, search for it on the menus.

Type in this command and press enter. The command will ask your
root password, type in and press enter too.

sudo apt-get remove apt-xapian-index

This will uninstall a non-useful search database for the package manager
which indexing takes a long time due to the CPU usage on low end CPU's
like the G3.

After that, type in command like the previous one:

sudo apt-get install rcconf whiptail

After you have installed those packages, run this command:

sudo rcconf . Use the cursor keys to go up and down, and the space bar to enable and disable. Disable cron, anacron and atd. JUST those. Leave the other stuff untouched. Press <tab> and <enter> to accept the changes. Reboot.

Finally, we will enable zram, which compresses the RAM at the cost of a tiny CPU usage. Use it on high end G3>600MHZ and up only. You could try it on a 
300 MHZ G3, but...

Yes, another command. Copy and paste it, and press enter as usual, giving the root password later. Don't worry, the script is safe, you could send it to 
a Linux user to check it if you think it's harmful.

sudo wget "http://bitbin.it/raw.php?id=owbzkUmp" -O /etc/init.d/zram && sudo chmod 644 /etc/init.d/zram && sudo update-rc.d zram defaults && sudo touch /etc/default/zram && sudo echo FACTOR=25 > /etc/default/zram && sudo reboot 

Done, now you have a virtual RAM disk, useful for 256-1G RAM PowerMACS (And intel PC's too) .

Sorry for my English, and give thanks to the ZRAM script creator.