how to send mail from gmail smtp server by using the ssis
There is a built in task for sending SMTP mail in SSIS.  If you want to use a script task to send mail via SMTP the post below lists several ways to do what you are looking to do.

http://social.msdn.microsoft.com/Forums/en/netfxnetcom/thread/a75533eb-131b-4ff3-a3b2-b6df87c25cc8