This is a new item just out today (10.25.04) and I haven't tried it yet.
Rwy12 Object Placer v1.0 is a new freeware program for placing static library objects in FS2004 in a simple and quick way. No need for scenery programming knowledge. Open FS2004 at the place you wish to add objects to (airport or just your neighborhood) shift to slew mode. open Rwy12, which is synchronized with FS2004, and chose your objects from a library that has about 300 objects in this first version. The program is open ended and we hope other scenery developers will add their creations to the library.
(dead link removed)