[cd34]

As for the first part, some companies do it differently. You might look for an httpdocs, public_html or www directory -- perhaps one of those directories exists. Normally you would connect to the assigned IP (assuming your DNS hasn't been changed).

Your domain registrar would be where you need to change the nameservers. You need to log into the place where you bought the domain, and change it to the NameServers that your new hosting company provides. They might list this in the welcome letter or a FAQ in the control panel.

DNS updates can take up to 48 hours depending on the registrar. Some Registrars do it more quickly. I registered a domain the other day and it was live within an hour.