Dave, I haven't installed Ubuntu on Apple hardware yet, but you should be able to dual boot it using the boot loader that comes with it. That's the way it works on other hardware.
As for installation, download a CD image, burn it (on a Mac, save the iso to your home directory, pull up a terminal, and type "hdiutil burn ~/ubuntu-7.04-desktop-i386.iso"), and boot off of it. It'll come up, let you run various applications, make sure that it found all of your hardware and such correctly. If it did, then you can use OS/X to repartition your drive to have a place to put it, boot off of it again, and click the "Install" icon on the desktop.
Some hardware it may not work on, which is why the "live CD" is so cool: you get to try out the whole thing without touching your hard drive.
As for installation, download a CD image, burn it (on a Mac, save the iso to your home directory, pull up a terminal, and type "hdiutil burn ~/ubuntu-7.04-desktop-i386.iso"), and boot off of it. It'll come up, let you run various applications, make sure that it found all of your hardware and such correctly. If it did, then you can use OS/X to repartition your drive to have a place to put it, boot off of it again, and click the "Install" icon on the desktop.
Some hardware it may not work on, which is why the "live CD" is so cool: you get to try out the whole thing without touching your hard drive.