There are many different ways to go about distributing your newsletter. First, there is email distribution. If you have a reasonable amount of clients, you can send your newsletter through regular email clients.
Installing a PHPList is another way to distribute your newsletter effectively. This particular software does most of the work for you. It knows what subscribers to send the newsletter out to. With this system, however, the maintenance and upkeep can be time consuming, so it is important to keep this in mind before you turn to this option for your newsletter.
Email services like Getresponse are another option for your newsletter. This option, however, can be costly. The cost is well worth it though in this case because this system will send your emails out at a set time. Again, it eliminates the work you have to do with your newsletter.
Nonetheless, when choosing how to distribute your newsletter, pick the option that best applies to you and what you are trying to do.