I only have a few more chapters to go, then I will post a "final" version of the book. I will be sending copies to several people before I actually post it so they can give their inputs on it; if you are interested, leave a comment and I will include you in the distribution.
I have decided to separate the core language from the GUI side, so I will be writing a separate book expressly about GUI programming. I have most of the rough draft done with that but I don't know when I will get a chance to write it (I'm moving overseas and probably won't have much time for a while).
I expect to have the book on this site by summer, so just keep waiting a little longer. I'm also going to see about getting it published and available for retail purchase. No guarantees but it will be interesting to see what happens.