My friend, the proud (switcher) owner of a new Mac, launched iTunes and said 'where's the eject button for the CD drive'?
Well there isn't one on most Macs. There is on recent Apple keyboards, and on the top right of laptop keyboards.
But, if you have, say, a Mac Mini that doesn't come with a keyboard ie you've reused an old one, ejecting disks may be tricky.
There is another way.
You can add an eject menu item.
Go to the desktop, find your harddrive icon, double click, then find and double click 'System', then 'Library', then 'CoreServices' and then 'Menu Extras'. Inside you will find an item called Eject.menu.This puts an eject icon in the menu bar.
An alternative is to use some freeware called Ejector which shows all volumes as ejectable.