How to see the print media CSS in Firebug?

Firebug is an excellent tool to to show a screen media CSS for some HTML element, but is there a way to look at the print media CSS too? Or is there any other tool to see the print media CSS?

What about Web Developer Toolbar?
https://addons.mozilla.org/en-US/firefox/addon/60
when installed go to CSS -> Display CSS by media type -> Print

Newer Firefox

1. Open devtools with F12.
2. Go to Inspector tab.
3. Open Rules subtab.
4. There will be print media button.

Old firefox

Firefox does not need firebug now.

1. Run developer toolbar by pressing Shift+F2
2. Type media emulate print

Type media reset in order to return to standard view.