[Hampshire] [OT] Wndows Bulk e-mailing software

The company I work for want to start sending marketing e-mails to it customer
database and e-mailing statements and remittances from the accounts department.
Now obviously we don't want several 1000 e-mail hitting the server at once, so
does anybody have any comments about any available windows based packages
please. We don not run an Exchange e-mail server, but a small basic e-mail
server system.

(If I don't reply it is not that I am ungrateful, it is because I am going a way
for the weekend)

Tim