There are a number of good Email Marketing tools out now, they've definitely come a long way since inception.
The great thing is that once you know your way around them, you're good to go - no need to be a designer!
Here are two great options that I use and highly recommend...
A popular lead-generation plugin for WordPress
OptinMonster is a lead-generation plugin for WordPress that allows you to create and integrate highly effective email signup forms on your website. It works with most popular email service providers and is becoming increasingly popular.
Easy to use email marketing platform
GetResponse is an email marketing platform and enables you to create a list of contacts, automate communications and is relatively simple to use.