The harddisk and monitor are icons from various icon collections, I know a lot of people are using Inkscape to create those.
www.inkscape.org/
Its a free open source program btw. Commercial applications for such a task could be illustrator, freehand or similar.
The red bar under the harddisk is probably made by Andy in FireWorks I presume.
Very nice find. I love finding things like this. ;D