How to show Child term in list box? I just want to know how to show child terms in list box see the below image



i tried http://drupal.org/project/hierarchical_select this module but don't know how to achieve this.

http://wimleers.com/demo/hierarchical-select/az-standards this is the link to achieve in Hierarchical Select, but no idea to implement this, hope someone implemented this.

or is there is any module available?
hierarchical select does support this feature. Just to conform you have created the field with term reference and set a proper vocabulary which has parent and child relation. and while creating the field you have selected widget as hierarchical select. Please follow this approach.