I have an intel dual core MacBook from last year.

I downloaded ubuntu-8.04-desktop-i386.iso, burned it using Toast, and let the verification complete. No problems.

I put the disc in, reset the Mac and hold down the C key. When the computer starts up, it reads the disc for a bit, then resumes booting into OS X.

Did I download the wrong image? Or should I burn with Disk Utility? Or? I can't get the CD to boot.