I haven't played the mod myself, but it's not too hard to add a tech. I'd recommend using Steph's expanded editor for Civ3
- it's a fine deal better than regular Civ3ConquestsEdit and has a nice graphical tech placer that makes placing icons on the tech tree more science than guesswork. Here's what you'll need to do:
*Open up Age of Imperium.biq (or whatever it's called) in Civ3ConquestsEdit. Go to the View menu, and choose Options (the last thing in the menu). Un
check the option "Compress .bic files", click OK, and then save the scenario.
*Now open up Steph's editor and open up Age of Imperium.biq. Go to the Tech tab, right click on the list of technologies, and choose Add Technology. Choose the "Use same name" options, and give your tech an obvious name such as Communism. Now set the correct prerequisites (era and technologies), and then click the Tech Tree Builder icon. This'll open up the graphical tech tree editor. Choose the era your technology is in, and a civilization, and then you'll be able to move the technology to its proper location on the tech tree. If you turn on the Graphic mode at the bottom right, it'll look just like it does in Civ3. Very handy!
*Now you need to add the government. Go to the GOVT tab, and right-click and add Communism and set the attributes as necessary.
*Now you need to add icons for your new government. Go to Civ3\Conquests\Scenarios\Age of Imperialism\Text (exact path may vary) and open PediaIcons.txt. Search for "# Small Tech Icons". This is the section that tells what icons to use for techs in the civilopedia. Go to the end and add something of this sort:
#TECH_Communism <--whatever you named it after the _
Art\tech chooser\Icons\12-Communism-small-vp.pcx <--the .pcx you want for it in the civilopedia - this is the Communism one.
Then go down to the "# Large Tech Icons" section and do the same thing, except for the big Civilopedia icon. Art\tech chooser\Icons\12-Communism-large-vp.pcx is the default Communism one.
I think the governments will automatically use the same icon as whatever technology they require. So this should be all you need to do.
You also can edit Civilopedia.txt in a similar way if you want a Civilopedia entry - this isn't really necessary if you remember correctly how Communism works when you're playing it (but would be a very good idea if you were releasing a full-scale mod).
Hope that covers it for this mod - if there's an error, post it here and one of us will know how to correct it. If you get more into modding, be sure to check out the tutorials around here - they're pretty good, even if it does require some time commitment to get the hang of it.
Oh, as for #1-2-3, like Steph said, it's up to you. But I'd recommend a cost similar to what other techs of the era are, and definitely have the Communal corruption flag.