Here's something I stumbled upon a couple of months ago and kept  
forgetting to share it.
If you are using Nib windows in your project, you can easily add help  
for any controls in your Nib window.
(buttons, checkboxes, edit fields etc).

There is no code to add to your FB project.
Just open Interface Builder and open one of your windows.
Click on a control and click on the Identity tab in the Inspector  
Window.
Enter your help text in the Help field.

That's it.
Now when your user holds the mouse over that control, they will get  
help in a yellow box.

Here is an an example of how it will look for a checkbox control:
http://macwise.com/_Images/HelpWithNibs.jpg

And here it is in Interface Builder
http://macwise.com/_Images/HelpWithNibs2.jpg

I don't know what the Extended Help box is for.
I have not been able to get that one to do anything.


Rich