Can I view my site before the DNS has propagated?

Windows Hosting

All websites are issued with an Instant alias based on the domain you supply that can be used as soon as the hosting has been setup. The format is yourdomain.com.ourdomain.com. The exact address will be part of the client welcome email

Linux Hosting

You can go to: http://your-ip-here/~theirusernamehere/. The IP would be found in your welcome email.