You could try a broadcasting service. They send them from their own servers and you pay a small fee per email($.005 - $.01 normally). You will also get tracking, bounce and unsubscribe management and a few other nice extras included in the price.
[edited by: hannamyluv at 9:30 pm (utc) on Jan. 5, 2004]
I got some cheap software called Prospect Mailer. It's dead easy to use and can send thousands of emails without slowing up the machine. I think I found it by typing "bulk email software" into G, but it was some time ago.