set node_id [site_node::get_node_id -url "/"]

    set child_node_ids [site_node::get_children \
			    -all \
			    -element node_id \
			    -node_id $node_id]

Beware that there is currently a bug in the call above in that it also returns the passed node_id (its 'self' is a member of the returned set).

Randy