Back-up Location

We are wanting to have a backup location of our server\network. It will basicly be a copy of what is already running with the exception of the internet connection. We are using a T1 and the backup location will use DSL. What will need to be changed so that people will hit the backup site if the home site goes down? One guy I here says as long as the IP's and the router settings are the same, we just need to turn everything on. I thought there would have to be a change in the DNS.

From your post I gather that you are talking about hosting a website and making sure you have a backup computer to host the site if the main computer goes down. In this case, you've basically got two options.

Firstly, you could set up the backup computer as you want it, ready for any situation. Then, when the main computer failed you would need to update your DNS records to point to the IP address of your backup computer. I don't know where the DNS records are being kept, but you'd want to be able to change them easily. However, if clients try to access the site, their own ISP DNS servers might cache the IP address of the server, so that they are sent to the failed primary computer instead of the backup computer. Changes to DNS entries can take up to 24 hours to be recognised everywhere throughout the Internet.

The other option is something which has already been suggested to you. If you could set the backup computer with the same IP address as the main computer, then when the first computer failed, you would turn on the backup computer and any requests for that IP address would go to your backup computer. However, since it sounds like you have your computers in two different locations, with two different connections to the Internet, I doubt very much that you would actually be able to make your backup computer have the same IP as your main computer.