changing IP address of MU installation - what do I do?

Hi

A while back I altered the Ip address of a domain/cpanel with wordpress on it. As soon as I did it I lost all my posts - they went to 404 pages.

I want to change the IP of my MU installation, and was hoping someone could tell me what to change in MU to ensure that the posts are found after changing the IP adrress.

Thanks.