thanks! - I'm still little lost though.

I have hosting through 123-reg. I currently run 2 sites, each using its own 'starter' hosting package.

I plan to run this site on a third account.

How do I log into this domain though? can I do this through the 123reg control panel even though it isn't mine? (provided I have the log in details)

Unless I set up another hosting account, I don't see how I can change the DNS information... surely I need the domain name before I set-up the hosting?