If you are hosting your site with MagicEdit but want to use GoDaddy's DNS, here is some information for how to go about it on GoDaddy. Other registrars will generally have similar setups.
Note: MagicEdit supports using your own domain name on paid accounts only. If you are using a free account, you can simply forward your domain to your free MagicEdit address.
Log in to your GoDaddy account and click the button that says My Account.
Under the section that says MY DOMAINS, click the domain name that you want to point to your MagicEdit account. Your "Domain Details" will open in a new tab/window.
Locate the DNS Manager link and click Launch.
In the CNAME (alias) table, find the row where the Host field says www and (1) click the checkbox. In the same row, click the cell next to 'www' in the "Points to" column. In the text field that appears, (2) type in your account name (example.cust.magicedit.com) and (3) click the button that says 'Save Zone File'.
Return to the Domain Manager screen by clicking the Domain Manager link at the top of the page. Under Domain Information, click the Manage link (next to Forwarding).
Type in your domain name, beginning with "www.", and click OK. Click OK again and log out of GoDaddy; your changes should take place within one hour.
Make sure to also set up your domain alias on MagicEdit.