Trade-In your Mac...
The answer is two folded.
At this time every CRT iMac is capable of running Linux. For certain models, you may require the latest Linux 2.4 kernels for proper hardware support. This is almost a requirement if you want to use external USB devices such as Zip Drives.
You should have good support for most of the hardware, including sound, video, modem and ethernet. Some hardware such as the DVD player and firewire may not be fully supported depending on the iMac and device you are trying to use. For more information on Firewire you should look at the Linux IEEE 1394 site.
As for the new LCD iMac, little is known so far about its ability to run Linux and if it does, how well it runs it.
The main problem with the new iMac and Linux is the NVidia graphics chip which has so far little support on PPC Linux. However, work is done on the NVidia drivers and having fully working and stable Linux drivers for the chips is only a question of time.
If Apple® followed the same internal modem policy than with recent iBooks and PowerBooks, then it will have a so called softmodem, requiring a special driver to be able to operate. Thus, unless we can find more details about such a driver, it won't work under Linux.
For more information on obtaining Linux for your iMac, refer to our "Where can I get Linux? page.
