WordPress MU

Hi
I've just bought a new domain name which will be linked with my current host account.
I'm just wondering how complicated it will be to transfer my wordpress MU installation to read this domain name. If I back it up now and reupload it when my host is connected with my new domain name how will I be able to change the website address within the wordpress admin?

Is there a step by step guide or do I need to install wordpress mu all over again?

Thanks
Judi

Please help me I want to know how complecated this is or whether I have to install wordpress mu all over again?

Any comments would be really helpful

If you do a search on here you should find an answer as it comes up at frequent intervals

Thanks but I still can't figure this out it seems really difficult, almost impossible.
http://mu.wordpress.org/forums/topic/8049

Am I better just reinstalling WPMU on my new host and importing my database files? If I did this how can I restore my uploaded media files to link correctly to my posts?

Thanks
Judi

I'm just a designer so I'm clueless when it comes to programming.