Do you mean VPS hosting or Domain hosting?
- If it's a VPS, go to Your Account, then press Hosting. You will see a list of your VPS's and Email Servers.
- If it's a Domain, go to Your Account, then press Domains. From there, you will see a list of your domains.
I believe that you can have as many of each as you need/want, as long as you pay for them.