Email program to send out batches of emails?

[songdancer]

I purchased the Pro Plus Package to build a friend's website, and I plan on using the AgentPress theme. The friend will have a list of about 3000 past customers that he wants to email periodically. However, from past experience, hosts don't allow you to send out more than 200 emails at a time. Therefore, I would like an email program (or plug-in) that I can add to OR use in conjunction with WordPress (link to it on a separate webpage on the same domain) which will let you organize a large email list in groups, so that you can send out small batches of emails. If the program will let you pre-program the time to periodically send out the small batches of emails, that would be even better. The contact list is in an Excel spreadsheet, so if the program can import from that, it would be a time saver.

What would be the best program to use for this purpose?

Thanks for any help as I start this project.