Hello ArminPasalic, and welcome to the Forums! 
If you want to make a MMO I want to ask you a couple of questions:
1.How much programming,3D Modeling,game design knowledge do you have?
2.Do you have a team that you are working with?
3.Will you KEEP GOING with the project even if you enocunter some problems?
Now,about making a MMO(not the tutorials):
I’ve seen alot of threads about people that want to make a MMO.
First off,you should know that creating a MMO requires a team,and it usually takes years of developing.Just think how much programming,and modeling you have to do,even creating basic stuff
World of Warcraft has been in development for 10 years,before they released it to the public in 2004,just think how many people worked on that game(day by day).
Now,I don’t want to ruin your idea about making a MMO,everyone wants to make a MMO!Even I wanted to make one 
Here are some tutorials that can get you started:
http://unity3d.com/support/resources/tutorials/3d-platform-game.html
This tutorial has basic stuff like animating a character,some AI,and other stuff in a platformer game.It’s useful in a MMO,and it teaches you the basic things.
http://www.youtube.com/user/TornadoTwins
TornadoTwins series of tutorials is about a simple worm game.It teaches you basic stuff in Javascript…It’s useful.
For more advanced stuff,asumming that you have enough programming knowledge you can take a look at:
http://www.youtube.com/user/BurgZergArcade
It a series of tutorials(like 160 videos…OMG!),that can help you A LOT in making of an MMO.
http://forum.unity3d.com/threads/29015-UniKnowledge-entry-Unity-Networking-the-Zero-to-Hero-guide
For making the game ONLINE,you need to know some basic stuff about networking.And the links above is one of the best tutorials that teach you about Networking.
For 3D models:
http://www.turbosquid.com/
You need to make an account first.Most of the 3D models have a price,but you can find FREE ones too.
You can also try the Unity Asset Store,there are some great stuff in there too.
Hope you will not give up in game developing(it’s fun)…even if you don’t succeed in making your MMO.
Good Luck,
-Robert-
P.S - Sorry for wall of text.