Donde encuentro algun tutorial para iniciar con jMonkey?
Where I found a tutorial to learn jMonkey step by step?
ACS
are you looking for tutorials specifically in another language or is english ok?
http://jmonkeyengine.com/wiki has a breadth of jme2 tutorials in english!
I'm having trouble following the tutorials there just to set up jME2 to show a window. Are questions supposed to come here, or to the general forum? Or is there other channels for newbie questions?
Questions should be posted in the general forum.
Make sure to have browsed the wiki:
http://www.jmonkeyengine.com/wiki/doku.php?id=user_s_guide
It is still sooo useful!
What tutorials you had problems with? With the flag-rush-tutorial or the turorialguide?
I tried following the latest jME2 with NetBeans tutorial, but it uses the development build, and the whole lib structure is different. I did get it to work in the end, although the whole experience was such a pain I'm going to take a break from trying jME2 and look at other alternatives…not that there seem to be any comparable engines around for the JVM. 
to be honest, jme is quite good to understand and there are a lot tests which are good demonstrations what you can do with jme.
allow me to ask how much experience do you have with "setup a project in netbeans/eclipse" or even program something in java.
It would be a good idea to learn those basics first. 