@sthreet nobody is able to edit your posts except the mod team and they do it sparingly (if something inappropriate or abusive terminology is used).

tiled would mapeditor.org

@sthreet don't really understand why you couldn't get gimp. There are at least 30 odd ftp and http mirrors to help you. See http://www.gimp.org/downloads/ . If you are on MS-Windows you just need a download manager although Mozilla or/and Chrome's internal download manager is good enough.

As far as morrowind is concerned, I'm not sure. While there are a few projects who are trying to have the same feature-set as morrowind, openmw comes the closest so far. See http://openmw.org/en/

Their idea is first to have it do almost all the things that morrowind has and then create and ask people to create original content so it becomes free and open-source in the truest form.

@sthreet lemme take a crack at explaining perhaps what is meant by open source games.

There are many gradations of what open source game is. The simplest way is where the source-code of the game is open. For e.g. if you see 'Doom' and any of the engines which is there, sooner or later that code is opened up so people can study it,use the logic and the code therein for their game. The source code can be licensed under many different licenses, one of the more popular is GPLv3 .The thing to understand here though is that while the source code is open, the art assets i.e. buildings, heroes, costumes etc. are not. 

On the other hand we have games such as 0ad, Battle of Wesnoth, Freeciv, Freecol, Konquest, Megaglest,SupertuxKart, FLARE and many others where both the source code and the art assets are shareable (You can google the names and download or/and play the different games I have listed above).Here the source code may be in gplv3 or some appropriate licenses and the art is in CC0 or something similar.  I am not getting into licensing because it can be a long discussion but just gave couple of examples so you know and hear them.

Now for why would people want to do that ? Because most of the Free and Open Source Software (FOSS) distributions (distribution is hundreds to thousands of FOSS software packaged both in binary and source form distributed via Internet or whatever method is good.) like Ubuntu, Debian, Slackware, Fedora etc. need software to make it compelling.Also it's a good way to share knowledge and letting others implement things.

Now what Opengameart.org does is providing a service so at one level people can use it as a sort of archive and art which is and can be re-used in different games.

Now how games do this, they use collaborative tools like git,mercurial,bazaar,subversion etc. and collaborate between themselves using the service somewhere.

Money is usually through donations from the community either through digital money or in kind (art etc.) .

One of the other things I would suggest is to not be over-ambitious, try going for a 16-bit or 32-bit game before going to something like you have shared above (as you said before you haven't done anything like before.)

Disclaimer :- I am just your average gamer. People in the fora are much wiser than me. This is just my opinion so take with few kilos of salt.

Is your game going towards something like an MMORPG or what ?  I am confused. If it is, could you please retitle it ? For people like me who are interested to find only single player games it would make life much easier.