If email marketing is part of your online strategy (which I highly recommend), it’s best if you use an email marketing program which will take care of most of the grunt work.
There are many email systems you could use, some paid and some free. It comes down to how many subscribers you have, how many emails you will be sending and the services you require. An all round excellent (and free) product is MailChimp, it’s easy to setup and easy to create campaigns.
If you have a MailChimp account but haven’t sent out an email yet, this video will help with creating and sending a simple campaign.