Hi,
Present the datastore of cluster 1 to cluster 2. Then create new cluster in vCenter 4.1, Remove the host from cluster 1 and it to new cluster in vCeter 4.1. If EVC is not enabled. If it is enabled, then you have to go ahead with your steps mentioned.
You dont need downtime for VM to move whole cluster to new vCenter server, if EVC is not enabled.
Regards
Mohammed