Yes you can have two domain names assigned to one account.
If you are using cPanel/WHM, you'll be able to set the primary domain name for the account on WHM. To set the secondary domain, you'll need to login to cPanel, and then add the domain either in parked domain names, or addon domain names.
See
http://www.eukhost.com/web-hosting/k...parked-domain/ for more information.