Service Unavalable

We are building a new website using wordpress on a Go Daddy. Last night when I went to log in to the admin page I got the following message Service Unavailable
The server is temporarily unable to service your request due to maintenance downtime or capacity problems. Please try again later. Apache Server at churchonmainstreet.org Port 80
So I cannot log in to my admin page and although you can see the website one of the pages also returns the error message. I went to wordpress support and this error 503 seems to be a server/hosting problem. I maintain other wp sites with other hosting companies and I have never seen this error. Any idea what the problem is. I really need to finish this website.
http://www.churchonmainstreet.org