This script is not published on userscripts.org, at least I haven't found it yet.
I'm still thinking whether to use it or not, since I play for 10 months now I can pretty much estimate how many cargos I need. It takes a day or two to get used to it, but it can be useful in times.
Anyway, the script adds the required number of cargo ships to steal resources in a spy report. You need Greasemonkey to use it.
Although it is written in portugese, you can just change the source of the script to say "small cargos" and "large cargos" in english, or any other language (I don't think the author will mind if you do ;) ).
To do that, open Greasemonkey options - either right-click on the icon in status bar, or go to Tools > Add-ons > Greasemonkey > Options. Then find Ogame Cargos Calc., and click on edit. A dialog opens, asking you to find the program you want to edit it with - WordPad (not Word) will be fine, Notepad might mess things up. When you have it opened, change the following to whatever you want:
Cargueiros Necessarios - Cargos necesarry
Cargueiros Pequenos - Small cargos
Cargueiros Grandes - Awesome huge slow cargos
The author claims this script works only on portugese ogame, although it worked for me on ogame.ba. I'll try later today on ogame.org, I need a few hundred deuterium for combustion drive, in order to be able to spy someone. Any offers?
You can check the authors blog for more info and a link to install the script.
Thanks for the mail ;)
Later update: works on ogame.org
More update: seems it doesn't work on .org. Showing zero cargos required.
One more update: the script is updated to work with ogame.org