This isn't mind reading, per say. Instead Bettina Sorger, Joel Reithler, Brigitte Dahmen and Rainer Goebel at Universiteit Maastricht have figured out a way to monitor the flow of blood in the brain and associate the images captured using an MRI with the letters of the alphabet. The whole system takes about an hour to learn and configure for each individual. Trials focused on healthy individuals, but clearly its the paralyzed and people suffering from diseases like ALS that have the most to gain. Sorger hopes to enable "locked-in" patients to finally be able to communicate with the outside world by thinking out letter at a time. Obviously, patients aren't going to be able to install an MRI in their homes, much less lug one around with them. The data collected could be used to finely tailor less accurate but more portable systems for patients that monitor electrical or light signals. If you're interested in the real nitty-gritty you can check out the complete research paper at the source link.