I stumbled on to some OS X icons today and thought it would be fun to use them. In OS 9 you select the document or folder whose icon you want to get and Get Info,select the icon, copy, close the Get Info window. Then you select the document / folder you want to add the icon to, Get Info,select the icon, paste, close the Get Info window.
In OS X it’s a bit different because there’s only one Get Info window — it simply displays the information for whatever object is selected at the time. Otherwise the process is the same: copy the icon from one object and paste it onto another. Interestingly though, whereas in OS 9 you can give an alias a custom icon, that doesn’t work in OS X.