I'm looking in a John Walkenback book and he seems to say that it's not
possible. You can add a description to the fuction itself that the user
would see before opening the function dialog box. Here are the steps he
gives:

1. Activate a worksheet in the workbook that contains the custom fuction
2. Tools Macro Macros (or press Alt+F8)
3. In the Macro Name field, type the function's name (note that the function
does not appear in the list of macros, you have to type it)
4. Click the options button
5. In the Description field, type a description for the function
6. Click OK
7. Click Cancel

Hope that helps

"Brad" wrote:

Thanks for taking the time to read my question.

I have made a function in my Excel workbook, and can select it from the
Insert - Function - User Defined list. When you select it, the dialog box
comes up in which you can enter the parameters.

When you select a regular function, there is help on each input and a
description.

Example: VLookup Dialog box has

Lookup_value
Table_array
Col_index_num
Range_lookup

Below these is a description of the function, "Searches for a value in the
leftmost column of a table, and then..." and a description of the current
input. Lookup_value for example reads: "Lookup_value is the value to be
found in the first column..."

How can I get this on my own function?

I hope this makes sense. If not, I can try to explain again.

Thanks,

Brad