Thought I'd share my primary sources for CE credit; feel free to comment and add yours!
(free!) ARUP Labs
(free!) Blood Bank Guy - selected podcasts qualify for CE credit through Wiley Health Learning. Listen to the podcast and take a 5-question quiz at WHL.
I also like paying for a year of LabCE in the year my certs are due. Currently this costs $95 for a year. I can finish up any credits I wasn't able to get for free, submit for renewal, then after my certs are renewed, I have the rest of the year to get a head start on the next 3 years.
Other sources I've been able to access free through an employer include Immucor and American Red Cross, but you need your lab's organization code to sign up.
Wait ours was circle circle dot dot - I'm suddenly feeling very unprotected against cooties!