Which one occupied Port 80

I enabled IIS 7 on one of my Windows 7 box. When I click start the default site, it always give me error. Said something wrong of the setting. Only when I change the binding port to other than 80, it works.
So, I think port 80 is occupied by other program.
Which one?
I google it and find the way to point it out.
1) Command line.
netstat -ano
netstat

I found PID 2448 took the port 80
2) Command line
tasklist
tasklist

So it is clear that Skype use Port 80


Why Skype use port 80? I don’t know. I can not remember I config it to do it.
Ok I go to Skype and click Tools > Options > Advanced > Connection
skype-port80

Uncheck the check mark to disable it.
Restart Skype.
It works. The site on IIS 7 can use port 80 right now.