Hi Srikantha
may be you can refer to some articles through link first below
http://learnsoapui.wordpress.com/you also can find the related presentation in soapui online document.
for example:
you want to add some script assertion to determine if the value return is correct
def groovyUtils = new com.eviware.soapui.support.GroovyUtils( context )
/*get xmlHolder*/
def responseHolder = groovyUtils.getXmlHolder( messageExchange.responseContent )
/*get namespace*/
responseHolder.namespaces['ns1']='http://www.webservicex.net';
def placeName=responseHolder.getNodeValue("//ns1:GetWeatherByPlaceNameResponse[1]/ns1:GetWeatherByPlaceNameResult[1]/ns1:PlaceName[1]")
log.info placeName
Regards,
Aaron