Hi Kiran,
Pranshu is right. In WCEM31, there are a couple of web services shipped by SAP which can be (re-)used or used as reference to create new web services. There is a detailed description about in the WCEM 30SP01 Development & extension guide. In a WCEM31 installation, I should be easy to play around a test the existing services.
Furthermore, right, the web services according to the OData protocol use the existing BO-layer of WCEM.
Best regards,
Steffen