Yes bulk email all at one go.

I am looking for newsletter system that can send 800k - 5millions.

Newsletters or spam? That seems like an awful lot of people opting into a newsletter. Most smtp servers seem to be setup to run in small batches of 50 or so and may cut you off if you try to send too many.

certify,

we are currently developing an interface for a mailer called limez. drop me a pm if you would like more info (do NOT add my email address to the mailing list =)

Yah, I've never seen a newsletter that's 100% voluntary sign-up with 800k subscribers.
But what do I know? I suck at everything :( hehe