Thinking animation to WPF when working a-sync

HI

I have list box that are getting data from service ,sometimes the service are taking about 15 sec to load the data

to the list box.

1. How can I provide some thinking animation while the list is loading (I want the standard windows thinking animation)

2. how can I change the list to work A-sync  i.e. when the list is loading the user can use the page since currently

the page is waiting to the response...

<ListBox
                  Visibility="{Binding IsLoaded,
                  Converter= {StaticResource BooleanToVisibilityConverter}}"
                  ItemsSource="{Binding ServiceData}"
                  FontSize ="15"
             HorizontalAlignment="Left" Margin="115,0"> 

This is the list box which is bound to the view model.

Thank you!