It is no good writing a solid content newsletter if no one gets to read it.
These days with emails becoming harder and harder to get to there intended recipients because of spam filters and the like you have to put in place a number of delivery systems.
In addition to email you should consider posting it on your website, setting up an RSS feed, linking to it from every angle, be it your blog, sig file in a forum post or whatever.
Writing the newsletter is the easy part, effective delivery is the challenge.
Just my two cents worth.
Cheers
Kevin Robb
