Hi Girish,
Static navigation is through plugs. We will define outbound, inbound plugs and then we will create a navigation link. This is how we do the static navigation.
In dynamic navigation there is no need of creating any plugs and navigation link. Within the event handler itself we can make use of interface if_crm_ui_navigation_service method navigate_dynamicaly for the purpose of navigation.
Check this link for dynamic navigation :
http://wiki.sdn.sap.com/wiki/display/CRM/SAP+CRM+WEBUI+Dynamic+Navigation+to+Activity+Create
Thanks and Regards,
DP.