Madhav.....As Ian commented, Camtasia is one of many very good tools for creating video. Last I checked, you can download a 30 day free trial from techsmith.com. Regarding learning to use, Camtasia has some pretty good help files. We've been using Camtasia now for a number of years to create ProE and PDMLink training videos. Additionally, the ability to create videos can be quite useful when dealing with Tech Support as a tool for communicating the behavior that is in question.
Regards,
Jim