Are there any animated models to start with for untalented ones like me? I googled and found several models but most of them are without any animation and/or so high-poly that they are unusable for a game.
Just a quite normal looking human model would be fine as a start to look into animated models with jME.
I tried myself with a 3DStudio model with bones but importing that one in jME shows the bones as boxes.
What is the best model format for animated ones?
I too am wondering the same, even more so to have the texture separate from the model so that the colours in the image can be manipulated at run time
if your talking about actually making animations I find maya easiest but it cost tons of money and if you can get illegally fine just don't get busted but on the free side there is blender. I haven't actually animated in that but it's open souce so it can't be to hard.
If your talking about importing into jme blender and milkshape are your options for joint driven animations. If your going for keyframe md3,md2 are support by a huge list of programs. have fun.
Gimme a general idea of what you'd like and in what format. I'll try to provide decent models with animation you can start with, excluding materials and textures.
I'm trying to build a MMORPG and once did a model but its head looks like a potato: http://www.world-of-mystery.de/client/ 
The model should be a human in a fantasy medieval world.
In this early stage I am, I would like to experiment with models and animation to get an idea how this works and to get a base client working to motivate others to join in. It doesn't really have to be beautyful, a simple male or female model is enough.
In 2002 I started such a project for the first time and in those days I used plib and C++ with OpenGL. I found some models that could be used with AC3D and plib had a program to store animation parameters using bones. The engine plib had a native read method for AC3D which made it rather easy to get a model animated. I had several other issues with plib but in this regard it was nice.
Using the AC3D model I soon found out that I don't have the talent to create a good looking model from scratch, but changing an existing one in a modeller is something I can manage.
jME is really great and I advanced much faster than with plib but I miss the comfortable model handling I had in plib sometimes.
One of the targets in my current project is to have several emotes so flexibilty in animation is one of the key points. The user should be able to choose from let's say a dozen emotes for his character and other players nearby should see that.
You see, I'm looking for a starting point and I would be more than happy to share the results once I have something up and running (in terms of dynamic model loading, controlling the NPCs, whatever).
Might I suggest using an open-content repository…oh, I don’t know…like http://www.logicalnetwork.com? :o
This way anything that you make available can be used by anyone.
darkfrog