@David_HarrisonApr 29.2006 — #The whole idea of the address bar is so that people can look at it to see where there are, or bookmark it so that they can come back to that page later, or send it to someone else so that they can also look at that page.
By hiding what page people are on you're destroying the entire point of having an address bar.
But yes, it's possible, should you really want to go that route. You can put all of your site into a frame. Though when people come into your site via a search engine, they'll be taken to the page with the actual content on, not the main page with the frame. For people who are browsing with the masked URL, it's fairly easy to get around too, for example, in Mozilla Firefox, users can simply right click the page and then click on, "Show only this frame".