Can someone explain what service opens TCP port 563 and uses it? I`m using Windows.
TCP port 563 is commonly used, or at least was commonly used once, for NNTP (USENET news transfer) over SSL. Most likely, the reason it's open on your particular machine has nothing to do with that though, and you should actually check what's using the port on your specific machine.
Right! Using netsat is the most simple solution.
If you want to have more detailled informations on what's running in yoir PC I suggest you to use MS TechNet sysinternals tools such as TcpView, Process Explorer and so on...
Check also this list of TCP-Ip ports: