4 on 21

Leslie Turek reports she worked with one of the original card counters (she was his supervisor, in fact):

... We all knew about his sideline - in fact, he often used our conference room after hours for card counting training and practice sessions. ... My favorite story is the day I walked into my office and found a clean-shaven stranger sitting there waiting for me. I had no idea who the person was until he spoke and I recognized his voice. JP had cut his long hair and scraggly beard in an attempt to change his appearance to evade the casino detectives. He was so thrilled that I hadn't recognized him, because he figured that if he could fool someone he worked with every day, it would probably work to fool the detectives. ...

Robert Buderi interviews John Chang (played by Kevin Spacey in the movie).

Chang has his own blog:

... I'd like to add a few words about the effect of all this publicity and attention. I expect it will encourage people to play blackjack. Unfortunately, from my experience most people will lose. ...

Will Ng writes he'll probably see the movie despite some financially-motivated racism behind it:

In actuality a majority of the MIT group were Asian, but Hollywood decided to cast Jim Sturgess and Kate Bosworth instead. Is this Hollywood's way of white washing a movie so it is more appealing to the general population? Yes. Does Hollywood think that Asians can't hold a lead role? Yes.