Link to the ePO 4.6 install guide
As for a PP 1.5 to ePO 4.6 upgrade path i think the only way is PP 1.5 -> ePO 3.6 -> ePO 4.5 -> ePO4.6 but seeing as you won't be able to get hold of a 3.6 installer it's a dead end.
Your best bet is a fresh ePO 4.6 install and manually recreate all policies and tasks and then add all of your clients systems in.
Message was edited by: Tristan on 18/06/12 12:23:39 IST
Cool, thanks for the link. Is there a way to get an existing agent to report to a new server? The agent will be from PP1.5