Hello and welcome to the GTK+ forums!
First, I hope you meant that you're using GTK+-2.24 and not GTK+-2.4 (the latter one is probably older than your PC).
You can get the information about item below the mouse cursor by tracking it's position and checking which item lies below. You'll need to connect to the GtkWidget::motion-notify-event and do the checking from it's callback. Code would probably look something like that:
motion_event (GtkIconView *iconview,
int x, y;
gtk_icon_view_convert_widget_to_bin_window_coords (iconview, event->x,
event->y, &x, &y);
path = gtk_icon_view_get_path_at_pos (iconview, x, y);
model = gtk_icon_view_get_model (iconview);
gtk_tree_model_get_iter (model, &iter, path);
/* Get data from model using iter and do your stuff */