The easiest way I can think of though would be to have your content in a Frame. One frame is 0% and the other is 100%. So it wont effect the look but when content is loaded up in the Frame, the URL bar stays the same.
However, even on sites with URL clocking (like NameZero sites) you can just right click the page or view it's Properties to show the full URL.
Please don't email or PM
me Flash questions, that's what the Forums are for!
Please don't rely on me reading my PMs either. Email me about important stuff.