How timely. I just added a note to this MSDN article yesterday to explain how to deal with multiple instances in a cluster when SSIS is not a cluster resource. This allows you to store your packages in MSDB rather than having to use the file system, which has the advantage of using server storage to protect passwords rather than a user key. The only other thing to watch is the DCOM permissions, and running agent jobs using a proxy tied to a credential that is a member of the local Distributed COM Users group on each cluster node is a great way to manage those permissions. This ensures that agent jobs will be successful regardless of which node an instance is running on.