Doesn't that usually only apply if you're using their mail server or relay? If your software actually connects directly to the recipient's ISP, there shouldn't be any limits on the number of emails you can send - as long as you're not sending spam and people don't complain.

Of course, you also need to be sending from a static IP connected to a domain name that the recipient can verify. If you're sending from your home computer (I've done this before), a fair number of your emails will be blocked because they're coming from a dynamic IP and/or look like they're spoofing the domain given as sender. What you really need is software running on your hosting account that connects directly to the recipient.

Incidently, Verio allows you to send pretty much any number of emails (within reasonable limits), so long as they aren't spam and aren't dumped on them all at once. I just leave my script running with an email sent every couple seconds and go do something else. A log of emails already sent will allow you to rerun the script if something goes wrong (though I've never had problems yet), without duplicating emails. Just remember to set Return-Path to a separate email box so you can easily analyze rejected emails.