You should be able to set your preferences in your browsers uhmn, Preferences.
What browser are you using, anyway?
I just went to the link in FF 2.0.0.4 and I didn't get any 'choice' display, it simply opened a small window and played the video. There
was a 'Preference' link on that window, I have RealPlayer selected. Still, FF gives one the option of assigning most any file type to be displayed/shown/played/presented with almost any plug-in/app of your choice. It's in the FF->Preferences->Content->File Types ( click the "Manage" button ). Your version and browser could be quite different.
I'm using FF 2.0.0.4. I went into FF>Preferences>Content>File Types and clicked the "Manage button". I changed the file type to QT, but it still would not play.
I went to the Real Player web site and downloaded Real Player and then tried it and it played OK!
Still the choices presented in the window were only WMV or Real Player.