Acceptance and Commitment Therapy is based on a theory of language and cognition called Relational Frame Theory (RFT). RFT is a much broader theory with much wider applications than therapy. For now, ACT is the most commonly recognized application of RFT, but other developments from RFT are coming, for example new educational tasks have been created that are being used to train students. Other researchers are looking at RFT preparations for training such basic skills as perspective-taking, a basic component of empathy.
Personally, I am most familiar with the ACT/RFT work on stigma and prejudice, as I have been involved in several studies on the topic. At least a few studies have been published to date and more are in process. One published study involved a 2.5 hour intervention based on ACT for stigma toward mental illness which had some positive outcomes. We are currently analyzing data from a pilot study on self-stigma in a population with substance use problems. A couple years ago a paper was published on an ACT intervention for stigma and burnout in addictions counselors. We are currently conducting a large replication/extension of that study that involves about 700 counselors. Like I said before, ACT/RFT are not limited to therapy, but really are about a larger agenda of the improvement of human lives. The ACT/RFT community is now trying to take on the issue of prejudice, discrimination, and stigma. If you care about this issue, you can join ACBS at contextualscience.org and join in the discussion.
One particularly interesting set of research involves an RFT-based computerized assessment procedure called the IRAP . This is similar to the more commonly recognized Implicit Attitudes Test (IAT) , but with a twist that allows there to be more control of what questions are asked and how respones are handled. The IAT and IRAP are both pretty cool methods that attempt to get at people’s impilcit/unconscious biases or preferences for various things. For example, the IAT has been widely used in research on prejudice. Various online versions are available. I just took an IAT test that attempts to get at your implicit attitudes toward various presidential candidates . According to my results, I have an implicitly positive attitude toward Barack Obama and an implicitly negative attitude toward John McCain. That’s probably not surprising to those who know me! 
I was inspired to write this blog in reaction to an online video on the IAT that I watched on which Anthony Greenwald and Mahzarin Banaji speak about psychological science in general and the IAT in particular . These are two of the leading researchers of implicit attitudes. The video comes from an organization called The Edge, which hosts a variety of really interesting intellectual and scientific discussions. For example, they recently showed a video interview of Craig Ventner, the person most responsible for decoding the human genome. Check out their website. Its a great resource.