You can easily add a wild card entry for your domain name through cpanel. Here is how you would set that up.
1. Login to your cpanel account (mydomain.com/cpanel)
2. Under the "Domains" column you will "Subdomains" click on this.
3. Under the Create a Subdomain section, you will see the input text box "Subdomain" enter * as the subdomain in there and leave all default settings.
4. Click on create button.