Forum Moderators: phranque
If your pages are already live and indexed I wouldn't bother - changing the filenames will return 404's for referrals from any inbound links/SERPS you already have (unless you set up a redirect)
I downloaded a free tool once to do this kind of thing, unfortunately I can't remember what it was called but it was a kind of text editor, and you could probably find it by searching on the net.