Creating an email newsletter using simplenews
I found this links useful

Designing a HTML newsletter for Drupal

http://drupalsteve.com/node/30



Drupal &amp; Simplenews

http://www.slideshare.net/desk02/dug-simplenews-6192093



Email Newsletters and the Simplenews Module
http://www.group42.ca/email_newsletters_and_the_simplenews_module



and probably

Newsletter subscription management in Drupal with E-mail Marketing Framework

http://www.drupalcoder.com/blog/newsletter-subscription-management-in-drupal-with-e-mail-marketing-framework