Hi Taiyeb,
SAP Netweaver Gateway is the technology based on OData for communicating.
Yes, after SAP CRM 7 EHP 3 upgrade, you need to activate the business function CRM_SLS_SRV_MOBILE_1 to get this functionality.
It has all standard sales and service related provided in it which are ready to use, just you need to maintain the customizing.
Hope this is useful.
Regards,
Naresh