1-Can anybody introduce some modern Petri-net editor and compare theme?
currently I am using WoPeD.
2-Is there any UML tools that also support Petrinet?
I have similar problem. In this article compared some tools for petri-net.
In my opinion the easiest to use is the Yasper but it not open source and works Windows only. I recommend beta version 2.0b22. The versions 2.1b1 and 2.1b2 not works in my Windows 2003 on Virtual Box.
Currently I am using PIPE2 because is open source, easy to use and platform independent. You may have a some problems with opening files saved in older version or other editors (such Yasper). I describe workaround in bug tracker.
I am looking for a editor for evaluation nets and I am considering to extend PIPE2 for support of this. Maybe someone has a better idea?