For your site, you may wish to set up more than one domain name that "points" to your website. For instance you might have example.com and example.net registered that you want to use for the same site.
The best way to do this, is to pick what you want your main domain name to be, and make all other domain names re-direct to the main domain. There are several reasons this is the best option:
The suggestions described above are all done at the server level within your hosting account, as they are not specifically software license related. Please contact your host for instructions on how to accomplish Domain Aliasing.