Yes, you can play Tabula Rasa for free until the servers are shut down on February 28, 2009.
The sci-fi MMO was launched over a year ago on November 2, 2007 and just did not get the following Richard Garriott hoped it would. So for now if you are a newcomer or former player you can play until the plug is pulled on Tabula Rasa. For the newcomer you can request a serial code from the support site to create an account, former players can just reactivate at the click of a button.
Hey maybe its not the best MMO out there but it is free.