Forum Moderators: phranque
There's no shortage of companies who can manage your bulk emails and newsletters - you can find a host of them with a quick search on any SE.
The interesting part of the question for me is what do you need to take this process in-house. Seems that it's very dependent on volume, and how scalable you need the solution to be.
Other issues to consider:
Make sure you are verifiably "opt-in" because if you get complaints to the e-mail your web site and or ISP account may get shut down/suspended (some actually shut down first and ask questions later).
HTML vs. Plain Text Newsletter (or both) - Impacts design time, skill level you need, and the design tools you will need (assuming you can't just do your HTML in notepad) and can also impact message size which in turn impacts the type of bandwidth you need to send the suckers out.
Middle Route - There are services online (for instance bCentral ListBuilder which let you send the mail and manage subs/unsubs through them but you actually create and send the messages online through their servers using their utility--I'm not affiliated just used them years ago when they bought out ListBot).
HTH.
Jas0n