MailChimp is very capable. Some really good management and analysis tools are provided if you need them. They also have several really good
guidebooks available for download that go into some depth about things email and what you need to know about it. Worth a look even if you don't open a MailChimp account.
I have a few clients that swear by MailChimp for their newsletters and marketing campaigns. MailChimp also provides a very capable free service if your needs are relatively modest (maximum of 2000 subscribers-all lists/12,000 email items per month). You can try it out - or use their free account indefinitely if that's all you need. They don't even require a credit card to set up a free account. That's really nice!
Addendum: one additional thing. Doing a
good newsletter, by which I mean one that's actually worth reading, isn't easy once you've written up your five or six favorite topics. If you want some inspiration, one example of a newsletter that really
was worth reading can be found
here. It was Iain Richard's old (and much missed)
Gizmo's Support Alert Newsletter. It ran from 1998 to 2008. To me and many others,
Gizmo's was always the model of how a tech newsletter should be done.
You can read all of the back issues online
here. Or download the entire searchable archive
here if you want to see more.
Note: I used to do a newsletter back in the late 90s which ran for 36 uninterrupted monthly issues. It became more and more of a chore starting around issue number eight. So if you do decide to do a newsletter, do what a magazine editor of my acquiantance told me to do when I started mine - have at least five issues worth of material before you publish your first. Because you
will get writer's slump sooner or later. And having half a year's worth of buffer between you and an uncooperative blank page goes a long way towards keeping you sane.