If your domain is registered with Godaddy and you are using their nameserver, you can follow these steps to add a new A record:

1. After logging in to your account, go to "My Account" area and click Domains.
   
   

   

2. Click the Launch button on the domain you want to add an A record to:
   
   
   

3. On the next page, go to the "DNS Zone File" tab and click on "Edit":
   
   

4. On the next page, clicking on an entry you want to update will make it editable inline. So you can make your changes right there, then just click the button "Save Zone File" when you are done.

   

5. To add a new A record, just click the button "Quick Add" at the bottom of the A (Host) section:
   
   
   
   This will add a new row of fields at the bottom for you to fill. Just enter the details you need and click "Save Zone File".