This blog will complement other blogs on 'Integration Directory API' in SCN.
Direct link:- How to use Integration Directory API
Helpful links:-
How to consume web services hosted by SAP PI / PO
Integration Directory Programming Interface - SAP Library
Assigning Permissions - SAP Library
Web service navigator: - http://<host>:<port>/wsnavigator
Single Service Administration: - http://<host>:<port>/nwa/ssadmin
Please search SAP SCN for more blogs on 'Integration Directory API'.