I want to make an E-Mail system which will be open by existing gmail/yahoo email id and retrive and send email to others and delete and manage the inbox

I am trying to make the project on online mailing system using asp.net but had a confusion how to start it and collect details to create it. please tell me...

I am trying to make the project on online mailing system using asp.net but had a confusion how to start it and collect details to create it. please tell me...