If you burn a data CD from the Finder in MacOS X, you can easily give the CD a custom icon by copying the icon and pasting it into the CD's info window. However, if you want to burn a data CD from Toast 5, giving your CD a custom icon that appears in OS X requires a little trick.
To find out how, read the full hint.
Before OS X, you could drag a folder with a custom icon into an empty data CD window in Toast and that folder's custom icon would become the CD's custom icon. This doesn't work anymore with OS X. What you need to do now is to save your custom icon as a .icns file (using a tool like Iconographer or Icon Composer) and drag it into your Toast window, placing it at the root level of your new data CD. Then rename the file as
.VolumeIcon.icnsOnce you burn the CD and pop it into your CD-ROM drive, it should appear in the Finder with a custom icon. :)
Mac OS X Hints
http://hints.macworld.com/article.php?story=20020306214108143