Click on the top BlackBerry border to rotate it vertically.
NOTE that Flash will not work on the BlackBerry, even though you probably see it working here.
You can preload a page or set portrait mode by passing using URL parameters, like this: http://iPhone-emulator.org/?url=www.sfusion.com
Pages in portrait mode are scaled to 75% by using CSS3 transformations, which work best in Firefox 3.6+, Chromium 5+ and Opera 10.4+.
The reload button on the BlackBerry address bar also works.