Roshan,
Fist you need to find out what are the competency certification requirement for SQL server, you can find that out here: https://mcp.microsoft.com/mct/program/competencies.mspx
In order for you to become a trainer you will have get your MCT (Microsoft Certified Trainer) certification. To become an MCT, you must complete these steps, as further detailed below:
1. Earn an accepted Microsoft Certified Professional (“MCP”) or Microsoft Certified Business Management Solutions Professional credential
2. Prove your instructional presentation skills
3. Obtain a Metrics that Matter ID
4. Apply to become an MCT and pay the annual fee.
Here is the MCT Guide: http://download.microsoft.com/download/2/7/2/27276EC5-2E0E-4E84-89E3-4B74922176F5/MCT_MCLC_Program_Guide_2009.docx
Hope this was helpful
