Does anyone know how I can retrieve (list) the descriptions of (user
defined or addin) functions and the descriptions of the fields of
those functions with VBA? I mean the descriptions that show up at the
bottom of the default excel function dialog.

[paulgu]

This page tells you exactly how to do that: http://www.cpearson.com/excel/vbe.aspx
Microsoft doesn't make it easy to do things with your code modules because this is a classic way for malware to cause trouble.