You can add users in bulk to Gmail Groups in your contact via a csv file. But you can only send 500 e-mails a day from each e-mail address. So its not really a sustainable solution.
I wonder what MailChimp's delivery records are like. Do you know if they have agreements with ISPs like the others?
http://www.mailchimp.com/learnmore.phtml See: Deliverability
Here's a nice comparison of them vs IContact: http://www.mailchimp.com/compare/
On an unrelated note, i like the clean design on Newscred. (Yeah. Nothing to do with the post but just thought I let it out)