One way to do that is to create a separate install of WP in a sub-directory - see:
http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory
Then it's fairly easy to switch over to the new site when it's ready to go.
One way to do that is to create a separate install of WP in a sub-directory - see:
http://codex.wordpress.org/Giving_WordPress_Its_Own_Directory
Then it's fairly easy to switch over to the new site when it's ready to go.