A question that has come up a few times in the last few days is whether App Controller works in browsers other than Internet Explorer 8 and 9.
The answer is yes, with some caveats and requirements. You can view the App Controller supported system configurations here: http://onlinehelp.microsoft.com/en-us/appcontroller/gg696060.aspx
For other browsers such as Firefox, Chrome and Safari:
Another note is that Silverlight 5 will not work with the App Controller Beta. This will be resolved for the final release.