Can't say it's technically free... but as a member of the AACN you have access to an unlimited amount of CEU's. Free in the sense you don't pay for the individual CEU, but you do have to pay to be a membr. You get more bang for your buck with AACN. The free CEU's you get from Medscape and others... is only 0.25-2 CEU's per article. The AACN articles are 2-5 CEU's.
Best of luck!