Michoud Assembly Facility
Michoud Assembly Facility is located in the industrial area of New Orleans. During the 1960s, Chrysler used the facility to make S-I and S-IB stages, and Boeing used it to manufacture S-IC stages. During the Shuttle era, Lockheed Martin used it to manufacture external tanks (additional information about the ET is available on KSC's site).
The Shuttle program having wound down, Lockheed Martin seems have removed most traces of Michoud from its website (although archive.org's Wayback Machine still has Lockheed Martin's main Michoud page as well as and their history page). NASA has a Michoud page on their Marshall Space Flight Center web site as well as a fairly detailed Michoud history page. There's also a slick MAF Fact Sheet [direct link to 1.6M PDF].
None of these resources, however, currently have the famous "Horsepower to Rocketpower" photo, so for that I'll direct you to MSFC's Image Exchange.
Google Maps link. The vertical assembly building is just to the upper right of center and the water tower is just to the lower right of center (easiest to find by following its shadow). Direct link to aerial imagery of the S-IC stage. Alas, I failed to adequately prepare prior to my visit and so didn't know that I had to drive an extra couple of blocks to the smokestacks outside the administration building, so for that I'll direct you to Google Maps.
I have a page with several vintage maps of the Michoud Assembly Facility.
"Michoud" is pronounced as a pirate might refer to his footwear: "me shoe."
We visited during the summer of 2005 (before Hurricane Katrina hit the area). Sitting just inside the fence on a corner of the property, the S-IC has a small parking lot dedicated to it ("Saturn 5 visitors only. Booster observation 30 minute time limit"). All of the pictures of the booster and the manufacturing plant were taken from the outside of the fence. Thus, either the fence will be visible in the picture, or the picture was taken with the camera lens up against the fence (and you may see the diagonal wires of the fence in the corners of the pictures).