Email Sending Limits
If you email is hosted through Google.com (write email@example.com if you aren't sure):
According to Google's policies regarding bulk email sending, for a Google Apps Standard you may send 500 emails per day. For Google Apps Premier account holder ($50 per email address per year) will allow for a 2000 emails per day, for a given domain max, but will still limit you to 500 emails per "Send". Read more about Google's policies here and here.
For a consistent list of contacts that would be receiving your emails you could set up a Google Groups. Information on Google Groups can be found here. Recipients would have to join your group to receive your emails.
Our product, Site-In-a-Box (SIB), has a newsletter tool that would allow you to bulk email your recipient list. This would require the purchase of an SIB website. You can contact our sales specialist firstname.lastname@example.org for more information.
There are many companies that specialize in assisting with bulk emailing needs.