Debian Net install
http://www.debian.org/distrib/netinst

Debian PowerPC
http://www.debian.org/ports/powerpc/

SheepShaver

An Open Source PowerMac Emulator

http://sheepshaver.cebix.net

Running Classic Software on an Intel Mac

http://atpm.com/12.09/classic.shtml

SheepShaver/Basilisk Tutorial

http://www.redundantrobot.com/sheepshaver-tutorial/