moving an existing working (physical) server to a new IP

I need to move a mandrake install to another static IP to host a few web based apps as well as the standard named, httpd and mail. I belive there is a firewall and spasmkiller as well. I know the server IP is fixed to the old one and don't know how to switch it to my new fixed IP as well as DHCP.

Can anyone point me in the right direction. My admin guy is not available for three weeks.

Thanks in advance.

Ok, cross-posting is not allowed on this forum, I answered in your other posting in the mandriva forum, so you should choose one and continue there...