Domains usually take anywhere from 15 minutes to 3 hours to propagate, although this process may take up to 24 hours.
Before a domain propagates, you can still access your website by going to http://yourIP/~accountName where yourIP is the IP address of the server and accountName is your account name on the server. Both your server's IP address and your account name are readily available in the "Welcome" email you received when you created your account with us.