The safest way to install it is to add an additional hard drive to your computer and install it on that. Like Frank suggested, download Ubuntu and try that first. It's very easy to install, and if you install it on the other hard drive, it won't damage your Mac installation. You will be allowed on start-up to choose which OS you want to boot. You really should try it. You will learn so much, and you will feel it's a very liberating experience once you start to feel comfortable with it.

Ok, thank you for your advices, i just download Ubuntu 5.10 and try the live cd first, it looks quite good and in that version ive got sounds, anyway i should install for try Pd and OpenMusic runing on Linux. Im not very smart about this stuff so maybe ill be disturbing a bit....

Ive got an external Hd drive with 5 partitions, 2 for Mac, 2 for windows and a 20G partition for Linux(i did it dont know why) Should i make a general Backup before installing? (im scared about install in a partiton and lose all the others things)

Any good link or software for my new linux experience will be apreciate,

thanks to all.