My business would like to send out a periodic email newsletter to our
customers.  I'm looking for the easiest, cheapest, most legitimate way
to do so.  I don't want it to get sorted as Spam and I'd like it to be
able to send text or HTML emails.  It could be a program or web-based
service.  It would be nice if it helped maintain the list too. I'd
like a list of options with links.  Thanks!

I have a small company and use the Mach5 (link below). It seems to do
the job, I think a lot of them are filtered out as junk mail, but I am
sure there is a way around that I just haven?t taken the time to work
it out.

http://www.mach5.com/products/mailer/