http://l4d2.gamebanana.com/tuts/10827

I'm not sure if this tutorial is out dated or not but it seems pretty simple! I thought I should post it here O: I'm going to try it sometime! c:

http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=414808565

Here's a terrific guide by Alex.marian about creating a mod for Typing of the Dead.

I found it very easy to follow, hope you guys do too!

http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=457643178

I wrote another guide about modding Postal 2 O:

This guide is about creating rexture/reskins for different things; like weapons, people, clothing, etc.

Tutorials/guides, suggestions, ideas, etc. go here! ♥

Please keep it on topic! No flames.

Tutorials/guides, suggestions, ideas, etc. go here! ♥

Please keep it on topic! No flames.

Tutorials/guides, suggestions, ideas, etc. go here! ♥

Please keep it on topic! No flames.

http://gtm.steamproxy.vip/sharedfiles/filedetails/?id=420457001

Here's a guide by J00sh about creating a mod in Postal 2 to replace the music files! I used this guide a lot when I made my music mods. Very helpful! c:

Tutorials/guides, suggestions, ideas, etc. go here! ♥

Please keep it on topic! No flames.

On the site minecraftguides, there's a wonderful guide about creating texture packs for Minecraft! The guide was created by Mute.

http://www.minecraftguides.org/how-to-create-a-texture-pack/

If you would like to search the link yourself, ask google "How to create a texture pack minecraft guides . org" and it should come up.

Mod the Sims also has a page dedicated to scripting mod tutorials.

http://nraas.wikispaces.com/Scripting+Core+FAQ

http://modthesims.info/wiki.php?title=Tutorial:Sims_3_XML_Tuning_Modding

http://modthesims.info/wiki.php?title=Tutorial:Sims_3_Pure_Scripting_Modding

http://modthesims.info/wiki.php?title=Tutorial:Sims_3_In_Depth_Scripting

http://modthesims.info/wiki.php?title=Tutorial:Sims_3_Object_Modding

I noticed that THIS page talks about your question - editing/adding values!!

http://nraas.wikispaces.com/How+to+Edit+XML+Tuning

Hope this helps! ♥