Showing Load Bar before entire page loads?

How would I display a load bar with the main page’s download progress until it’s finished downloading? Basically, I don’t want anyone to see the site until everything has loaded. This is a site in frames, so each frame would have to load before anything appeared. I have around 9 frames. I have figured out how to show the progress bar when downloading a flash file before it’s displayed, but I’m not sure about how I could do this for an entire HTML/Flash site with many frames. I would really appreciate any help you can provide.