Question: i would like to learn the theory cellular automata and know more about the research being done in this field and the links with other related fields such as artificial inteligence, computabilty and language theory.
Any recommended books and online courses?
great!!! thanks a lot for your answers!!! (it says comments are not for thanks lol)

Answer: 
I really like the book *"Cellular Automata and Groups"* (which is in the link on the other topic on mathoverflow). [Here](https://dl.dropboxusercontent.com/u/8592391/bok%253A978-3-642-14034-1.pdf) is a link for download it.

This book is very complete and reader-friendly. The appendix is very well done, all the proofs are extremly clear. Moreover, lof of nice topics are treated, for example amenable groups (the Tarski theorem is proved in an elementary way).

At the end, there is also a list of open problems and 7 or 8 pages of reference.
Have a look at the [lecture notes](http://users.utu.fi/jkari/ca/) of Jarkko Kari or his [survey article](http://dx.doi.org/10.1016/j.tcs.2004.11.021).