I'm not sure if this should be in this forum.

Does anyone know what programs are needed to add an ILS to an airport?

garymbuska wrote "AFCAD will do this for you.   "

This Isn't the complete picture.
Taken from the AFCAD manual file.

"The NAVAID information contained in facility files does not have any affect on how your aircraft’s instruments work. That information actually comes from visual scenery files, which AFCAD doesn’t deal with. For example, if an airport you fly into has a misplaced localizer beam, this won’t allow you to fix it. You can use a third party freeware utility called EasyNav to do that. The NAVAID information in facility files is just presented for information purposes on the FS map view and GPS windows. However, it can be informative to see where the NAVAIDs are placed (or misplaced) at an airport. It appears that any errors in placement for the NAVAIDs you fly with are also contained in facility files, as the data was derived from the same database. If you can manage to correct NAVAID errors in the scenery files then you can make the corresponding correction in the map view using AFCAD." copyright © 2003 Lee Swordy

The above being said, you do need AFCAD.

You can find EasyNav Here:

http://prevair.free.fr/default.htm

Hope this helps.

Oh!
I got the program from another site and the web ref from the documentation.
However, I have used the 3.51 version on FS2002 to create an ILS on an airport I created using AFCAD with no apparent problems.

Are you trying to do this on FS9 (FS2004)? If so I'm sorry, I have no idea what you would need (unless the new version of AFCAD for FS9 really does do it all).