AttachedProperties.cs

public static class AttachedProperties
{
    public static DependencyProperty ItemClickCommandProperty = 
        DependencyProperty.RegisterAttached("ItemClickCommand",
            typeof(ICommand),
            typeof(AttachedProperties),
            new PropertyMetadata(null, OnItemClickCommandChanged));

    public static void SetItemClickCommand(DependencyObject target, ICommand value)
    {
        target.SetValue(ItemClickCommandProperty, value);
    }

    public static ICommand GetItemClickCommand(DependencyObject target) 
    {
        return (ICommand)target.GetValue(ItemClickCommandProperty);
    }

    private static void OnItemClickCommandChanged(DependencyObject target, DependencyPropertyChangedEventArgs e)
    {
        var element = target as ListViewBase;
        if (element != null)
        {
            // If we're putting in a new command and there wasn't one already
            // hook the event
            if ((e.NewValue != null) && (e.OldValue == null))
            {
                element.ItemClick += OnItemClick;
            }

            // If we're clearing the command and it wasn't already null
            // unhook the event
            else if ((e.NewValue == null) && (e.OldValue != null))
            {
                element.ItemClick -= OnItemClick;
            }
        }
    }

    static void OnItemClick(object sender, ItemClickEventArgs e)
    {
        GetItemClickCommand(sender as ListViewBase).Execute(e.ClickedItem);
    }
}         

AttachedProperty.xaml

<ListView IsItemClickEnabled="True" 
          ItemsSource="{Binding Items}" 
          local:AttachedProperties.ItemClickCommand="{Binding ItemClickedCommand}" />

ViewModel.cs

public ViewModel()
{
    ItemClickedCommand = new DelegateCommand<string>(ItemClicked);
}

public void ItemClicked(string item)
{
    // react to the event
}