Temp install directory

Hi,

I have a website which is already up and running. I want to move it over onto WP – but do not want to take down my site whislt i buld the WP version.

Can someone suggest the best method which will allow me to build the WP site in the background and then change the index file and everything will point to the worpress site on launch day?

I have a feeling that if I install it to a new dir and then move it to the root this may caue problems!

thanks