Change Hostname and server

Ok, I did a search and did not find any topic about this so please forgive me if I missed something.
I am starting with WP and have a small site up and running. I am using my home box and using a dyndns.org account for dns resolution to it. It was working successfully until the day I messed with it(figures). I had a hostname and I wanted to change it. I registered with dyndns.org and proceeded to update my main WP config page. The problem is this: I updated the host information in the config page incorrectly so now all the links from the index.php file point to a site that does not exist. Since I cannot login(it tries to go to this phantom site), is there a way to manually update the configuration so it points back to the dns entry that I know works? If anyone out there knows what I’m talking about and knows how to fix it I would appreciate it.