logon/logoff times for users in domain

I’ve seen several topic brought up about this subject but I haven’t seen any that answer the question that I am posing. I am currently a system admin for an all 2k network with 4 domain controllers. I have been given the task to get a logon\logoff times for all of the 50+ users on the network on a weekly basis. While I’ve seen the policies that can be set to audit logons but with multiple domain controllers, this can take forever to gether. Is there an easier way to collectively gather this information rather than this manual process? Thanks