ANY LINUX for my old IMACs?

Ubuntu and other mainstream distros won't work with your iMac, as they won't support all the custom hardware and boot method of the G3 iMac. It may not be easy getting linux to work on this machine, but there are reports that Yellow Dog Linux, version 4.0.1 will work:

http://lists.terrasoftsolutions.com/pipermail/yell...

You can get the ISOs from here (4-disc set?):

http://mirror.anl.gov/yellowdog/iso/

It that doesn't work, you may need to run either MkLinux or LinuxPPC:

http://www.jonh.net/lppcfom-serve/cache/350.html

http://www.mklinux.org/

Some other links that might help you out:

http://lowendmac.com/linux/index.shtml

http://www.jonh.net/lppcfom-serve/cache/350.html

Older Ubuntu versions run on PPC MACS. There is also a distribution called Yellow Dog Linux that is supposed to run fairly well on older iMACS. A quick search and I found an old article on how to install Yello Dog Linux on an older iMAC (see the link below).

I'm sure there are other Linux distributions that run on Apple PPC machines, Linux.org would be a good place to look for others if you can't find an older Ubuntu of Yellow Dog distribution.

You can try one of the older versions of Ubuntu, if you can find one for download somewhere. All versions previous to 7.04 support Power PC.