Email marketing software can help companies automate and refine their programs, providing the tools and technologies they need to optimize results and boost campaign ROI.   Email marketing is a very versatile medium. Messages can be formatted from simple text all the way to HTML & rich media. Content can be one-size-fits-all  out of the box or highly customized. Frequency of emails can be set at a fixed time, frequent intervals or sporadic intervals, all the way to transmissions occurring only when something newsworthy comes along.

Do a search on one of the internet search engines and you will find a multitude of service providers at your fingertips.