A few days ago Google announced the end of the free tier for Google Apps, a way to have a Gmail account with a custom domain. That's a pity! Paying $50/year for each mail/user it's ridiculous and it's out of the question, set up a mail server on the server it's something I don't want to do it anymore (I was doing it in the beginning, but it was giving me too many troubles), let's see a good alternative.
For example, we can set a custom-domain email on Outlook.com on my new domain Forexperiments.com
    - Go on http://domains.live.com
 
    - Insert the domain name and set Windows Live Hotmail
    
 
    - Create an Admin user
 
    - Accept the terms of use
 
    - Set the DNS as instructed (Unfortunately, if you use a cheap registrar like mine, you can't set TXT field and make messenger and the domain verification work...)
 
    - Wait some minutes for the DNS records to propagate (If you use a cheap registrar like mine, wait some hours...)
 
    - Done! Configure users and give them an Outlook.com account, instead of a Gmail one! Moreover, the new interface is very nice and easy to use, even for newbies