Microsoft's widely used e-mail service Hotmail was recently overhauled and rebranded Outlook.com. One of the less known services they provide is the support for custom domains. A couple of months ago, I was looking for a new (preferably free) e-mail service for my personal domain. It turned out Outlook.com had everything I needed!
To set up a custom domain, you'll first have to log in to the Windows Live Admin Center with your Microsoft account (I used my good ol' Hotmail account). There you'll add your custom domain, and you'll get instructions on how to set up DNS etc. You can choose between closed membership, i.e. you'll register the e-mail accounts yourself, or open membership which lets users register e-mail accounts under your domain themselves. The setup was straightforward, so I won't repeat the steps here. You initially get a limit of 50 e-mail accounts for your custom domain.