If you're interested in learning Automata from Prof. Jeff Ullman of Stanford you may join the current session on Coursera. What's best about this course is that Prof. Ullman is always present in discussion forums, and helps everyone learn and enjoy great discussions. Join here https://www.coursera.org/course/automata
Edit: I'm currently learning there, and enjoy it a lot. Especially in video 6, you may listen to the stories of Junglee startup, Started in the mid-90’s by three of his students, Ashish Gupta, Anand Rajaraman, and Venky Harinarayan. Goal was to integrate information from
Web pages. Bought by Amazon when Yahoo! hired them to build a comparison shopper for books. They made extensive use of regular expressions to scrap..."
The Coursera Automata course is awesome. Ullman's active participation in the current second offering is part of it. But what really makes the course for me is that Ullman's presentations are relaxed. He knows the material, he knows where various aspects of the material rank in terms of importance to the learner, he has a feel for where students will get hung up, and he has no need to prove anything.
Ultimately, this gives the class the feel of a graduate seminar. It is designed so that student's can readily succeed in learning the material rather than structured around the idea of weeding out weaker students. It assumes that anyone who wants to learn the material can with enough effort, and that that learning is really all that matters.
In addition to the lectures what has made the course interesting to me is the vibrant, active "Discussion Forum" associated with this course. Ullman himself frequently posts explanation on some of the topics here. It seems there are some takers of this course who are well versed with Automata theory. Some of them are quite active in the discussion forum providing good explanation to many of the trickier concepts introduced in the course (which has been immensely valuable to me).
Automata is the third Coursera course I've taken [the first session of Introduction to Systematic Program Design and the current session of Programming Languages are the other two].
One of the features [or bugs depending on how you look at it] is that a lot of the forum participation is by people who have largely mastered the course material. This can be great for someone who is ok when the smartest person in the room turns out to be someone else [HN helps me develop this habit]. But at times, it is intimidating for students coming to the material for the first time or who are struggling.
The discussions in the Automata course are way out of my league...plus I'm not fully invested in keeping pace with the material right now. In the Programming languages course, I participate, but I find posts saying "this homework was really easy" unhelpful when I've spent twenty or more hours wrestling with the week's problem. I imagine that it can be downright discouraging to someone struggling just to pass and unable to devote as much time as it takes to solve it.
That said, the discussions in Automata are first class - right down to the formatted mathematical expressions, and I find the topic fascinating in and of itself.
If you are interested in going deeper, may I recommend "Parsing Techniques" by Dick Grune et al [1]. I have read this book over five times and still find gems hidden that I must have failed to grasp in a prior reading.
The author provides the PDF of the first edition on his website [2]. Read the last paragraph of page 60 of the book (page 50 of the PDF). I read this again whenever coming in doubt.
A great thing about the book is also its annotated bibliography. The author cites hundreds of papers for extended reading, but has also written a paragraph on each cited paper explaining the context around it, how it fits with the rest of the subject, and a quick summary of what were the key contributions and findings.
From my dim and probably exaggerated memory of a visit, his cubicle was pimped out witch-doctor style. (They had a jungle theme around the office floor in general.)
Edit: I'm currently learning there, and enjoy it a lot. Especially in video 6, you may listen to the stories of Junglee startup, Started in the mid-90’s by three of his students, Ashish Gupta, Anand Rajaraman, and Venky Harinarayan. Goal was to integrate information from Web pages. Bought by Amazon when Yahoo! hired them to build a comparison shopper for books. They made extensive use of regular expressions to scrap..."