change cursor

Ever since Windows 97, it was possible to change the shape of cursor. For exmaple, rather than the pointy cursor, I could use another icon or upload an icon of my own to the cursor. I'm using osx 10.7.4 and i cannot change the icon of the cursor from a pointy thing to something else. There apparently was something called mighty mouse but it doesnt work on 10.7.4. Is there anything out there at all that I can use?