304999 Email marketing

I need to develop a system in c# or Java for sending e-mail marketing. I just need the engine to send the emails, the web platform to manage all the system is already available, but the lack of transmission system that will have to communicate with the existing database in MSSQL 2005, get data from the campaign and mailing list and send the email marketing. The system must have capability for sending 10 millions emails a day. Must be done with threads. Thank you