Skype is a great tool to teach online , for this i want to know how this can be done more effectively , i basically want to know what tools can we used for this.

Like for while teaching what tools to used for screen capturing if i want to show some work to students.

Is there any tutorial available specially video tutorial, can you give me link to that , i basically want to know the best and effective way of teaching using Skype specially i want to teach math and accounts.

Also want to know that is webcam is necessary to teach online.

Thanks in advance.