I made a little package with the Tutorials (&Guides, Manuals, Walkthroughs) I could find about MoH:AA/SH/BT.. before they disappear from the net.
Hopefully it will be of some use to you guys!

It includes tutorials about mapping, modding, skinning, scripting, modeling, software etc.
It also includes guides and lists about general mohaa stuff (player models, taunts, cvar lists etc. etc.).
Some software is also included (pakscape, radiant, SDK, milkshape, mbuilder, lightray etc.), a few plugins for these software have also been included. 
Some of the tutorials also include pk3's, .map files, .scr files etc.

They are categorized in folder by the name of their creators (or website of origin). 
This because a lot of information should be combined and not copied into many different folders. 
Didn't really know of a better way to categorize them, so if you want to categorize them differently, be my guest ^^

Any video included with tutorials is best opened/viewed with VLC mediaplayer.

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There's a Table of Contents document included which shows all folders, including all documents, chapters & subchapters for easy searching.
Just use CTRL+F within the Table of Contents and use a specific keyword.. and any Folder, Document, Chapter or Sub-Chapter with that keyword in it will be shown.
Try synonyms of the same keyword if you don't find any results.. There's of course still a chance you won't find directly what you'll want..
Which means you'll have to look through the tutorials related to your keyword yourself.

There's an Updates document included which shows all updates (new additions) since the previous versions.

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If you're looking for any MOHAA/SH/BT resources/downloads like custom maps, mods, player skins, weapon skins, guides, tutorials, prefabs, patches etc.
Please visit: http://www.mohaaaa.co.uk/AAAAMOHAA/content/downloads-and-resources
AAAA currently has the largest MOHAA Resource Database online.

This website also contains a lot of custom maps that were made with the purpose of using them as a Tutorial/Guide for other people.
These maps mostly include .MAP files and other important files that might help a mapper out (scripts, readmes, pk3s etc.).
To find these Tutorial Maps, go to the Map Database here: http://www.mohaaaa.co.uk/AAAAMOHAA/content/map-sort-view
Then in the Title Search, search on either 'Tutorial' or 'Test' to find the biggest portion of these maps that are made for learning.

There is now a Prefab Package and MAP Source File Package available on xNULL as well.
These packages include every Prefab & .MAP (source) file that has been found online (with creators mentioned where known).

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Don't forget about the MOHAA Guide that also includes a lot of nice information :) About 185 pages about all of MOHAA.
The Guide is hosted by AAAA & xNULL, some other sites have hosted older versions as well.
You can download the new Guide (V1.5) at the following locations:
- http://x-null.net/tuts/MOHAA_GUIDE_V1.5.zip
- http://www.mohaaaa.co.uk/AAAAMOHAA/content/mohaa-guide-v15
- http://www.mediafire.com/file/svw0vq1vo64cwoz/MOHAA_GUIDE_V1.5.zip

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Kind Regards,
Shadow (Brian)