All accounts can host more than one domain (Domain pointing to sub-domains).
You can add a addon domain to you account by doing the following:
1) Go to your control panel, go to 'Addon Domains'.
2) In the 'New Addon Domain' field, enter the domain you wish to point to a sub-domain of your account.
3) In the 'Username/directory name' field, put the sub-directory name you wish to use. For example, if you choose to use 'sample', the subdirectory sample.youdomain.com will be created for the addon domain.
4) Choose your desire password. The user name and password will be the ftp login for this addon domain.
You can add as many addon domain as you wish to your account limit. Each addon domain will have its own ftp login. You account space and bandwidth will be shared by the addon domains.