Nestled away in the overview of of Version 1.3.2 "Path of Conquest" in this month's WAR newsletter are details of some pretty significant changes coming to Warhammer Online.
This month's newsletter reveals that the currently available 10 day free trial will soon be free of any time restrictions, meaning that players can essentially play the game free of charge as long as they remain in Tier 1. This sounds awfully similar to the "Freemium" model that the Chronicles of Spellborn had been utilizing not long ago.
There aren't currently any details on whether or not any additional restrictions would be applied, though it would probably be safe to assume that any restrictions (such as being limited to Tier 1) that are currently part of the 10 day trial would remain.
For more information about the Free Trial, read the Trial FAQ here.