to install active active sql cluster

Hi all, My aim to install active/active 2 node SQL 2005 cluster. I have installed sql cluster on one mode, which automatically installed on node 2.
it works great. However When i tried to install second virtual server, it is not allowing me to install.
it says already install, can anyone tell me how to install active active cluster

i think i got answer, im installing second node as default instance. i have to use named instance for second active cluster. however, we have be cautious about crm 3.0 work around to support named instance