change url structure

I want to change my url structure for my wp site. Like wp url structure for about us page is http://www.domain.com/it-will-look-like-this. But i want the url structure as http://www.domain.com/It_will_Look_Like_This. That mean first latter of every slug name is capital latter and (_) instead of (-). I want this url structure every page of wp website.

Thanx in advance.