newbie imac problem

Just bought a imac g3 and I'm trying to install a linux distribution on it with the specific ppc cds. Everything was going fine until a encountered an error on one of my cd discs, I manually rebooted and reinserted a new burn of the image, but for some reason the downloaded image must be corrupt because its not booting and I can't for the life of me figure out how to get the disc out of the drive. How should I go about getting the cd out, I'm not that all familiar with imac bios or keyboard shorcuts, there has to be something I'm overlooking. The imac is brand new just can't get anything to run since I tried to install linux...I reformatted the drive and all I get is a mac logo on a folder icons blinking with a question mark. If I could just get this disk out of the machine I could try another burn of the software....what am I overlooking.

Reboot and hold down the mouse button while it boots up and the CD should eject.

Well thats sorta another problem I am having. One of the reasons I am trying to install linux on this machine is that the mouse isn't being detected. It the Microsoft Optical Wireless elite. The keyboard works but the mouse doesn't.

finally, I got the cd out, I finally found a site that explained the problem. I had to boot into open firmware and type eject cd holding down command option o f.