Symptom
There is no apparent "Password pane" for showing hints when logging in to Mac OS X. There is only a Password field.
Solution
1. Choose System Preferences from the Apple menu.
2. Click Login.
3. Click the Login Window tab.
4. Be sure the checkbox for "Show password hint after 3 attempts to enter a password" is checked.
5. Click Show All.
6. Click Users.
7. Click the name of the user you wish to have a hint.
8. Click Edit User.
9. Type the text you want in the Password Hint field.
10. Click save.
The next time this user enters the wrong password three times while logging in, an alert box should appear that contains the hint.
Note: In the Mac OS X 10.1 release, the Users Preference pane on the Password tab provides a field to enter a password hint. The Login Window tab of the Login Preference page is still used for allowing/disallowing password hints.