Yellow Dog is a nice PPC Linux distribution, but I personally prefer
Debian PPC, mostly because apt-get totally rocks. However Debian can be somewhat difficult if you're a new Linux user, so you might want to look into
Ubuntu for PPC, which is based on Debian but made for new Linux users.
Why run Linux on a Mac?
- If you need a server-level OS but don't want to pay a license for Mac OS X Server.
- If you have an older Mac that performs poorly in OS X, like one of the first iMacs.
- You think Apple's hardware rocks but don't necessarily need all the eye candy of OS X. Mac Minis make awesome little servers.
I run OS X on my desktop and notebook, but have Debian on an older G3 iMac, which is a half server half kitchen kiosk.
If you want to check out Linux on a Mac without installing download the Ubuntu
Live CD.
BTW, the Linux version of GIMP actually supports Arabic. Running it from my Linux machine in OS X's X11 comes in useful; same with the Linux version of OpenOffice.