Now that you have the system set up for you emailing you can concentrate on the emails that you will be sending and how you can format them to get them out correctly.
Some people are very old school and say that the best way to send an email is by sending it as text only and formatting it so that you will not have any problems having it read as you would like. The best way to send an email in text format is to type it in Word or Word pad and after 65 characters you his the enter key so that none of your lines are over 65 characters of text in length. After you have done this formatting you can save it as a txt file and the open that and copy and paste into the email at your Auto responder service.
I am a bigger fan of HTML type emails and believe that these are the best to send out as you have complete control over the email. You can format the email as you wish, add pictures, ad hyperlinks to other sites and make a much better presentation to your customers. Nowadays you will find that HTML is accepted by all true email clients including Outlook, Outlook Express and Thunderbird. The one issue that you will have is that email programs automatically block pictures. The reason that pictures are blocked by email programs is that spammers used to be able to track email addresses by sending the picture and therefore knowing whether an email address was active or not.
Just a couple of tips here on email as I will dedicate a post to email copywriting itself later.
Make sure that your email includes an opt-out in case the people decide that they do not want your emails anymore and would like to say no. This is really a bridge to your credibility; you are showing your readers that they do not have to receive this but that they do because they want it. In the same vein you should also let people know how and when they subscribed to your mailing list. This reminds them how the email that they are reading is not spam.