Different sidebar for each category?
 

Are there any plugins to do that? (talking about wordpress)

Make a different template for each category is the easiest way to do it.

http://codex.wordpress.org/Category_Templates

You could create a new template for each category, as Gothbox suggested, but a more efficient way would to be add a statement to your sidebar that instructs WP to display a different sidebar if the post category=x.

This question was answered in this thread:
http://www.gofuckyourself.com/showthread.php?t=798940