fdmaxey's answer is the best in explaining the differences in the meaning of the two sentences.

I don't think a native English speaker would say "This book has been written in English." That sounds very strange, at least to my uncultured American ears. :) If we were to substitute the word "published" for "written," it would be easier to show the difference in meaning between the two constructions. "This book is published in English." This would mean that you can buy the book in English, and maybe even Greek, Swahili, and Sanskrit. "This book has been published in English." This would mean, as of the present moment, someone published the book in English in the past. It possibly is or is not available to buy in a bookstore; maybe it is out of print. All you know is that, in the past,someone published it in English. Let's try it with another verb to see what happens, just for the sheer joy of it. :) My child is bitten by a dog every time we come to this park. (Do you see that this sentence is just the passive of "A dog bites my child every time we come to this park?") It means the same thing. versus "My child has been bitten by a dog every time we come to this park." (This is just the passive of "A dog has bitten my child every time we come to this park.") It means the same thing. The difference in meaning between "is bitten" and "has been bitten" is almost nothing here. Maybe the first sentence with the "is bitten" would imply the mother expects a dog to bite her kid the next time they visit the park. In the "has been bitten" sentence, you are looking back at all the dog bites that have happened. But still the mother would expect more dog bites in the future. So I can't really see any difference in meaning between "is bitten" and "has been bitten."

If I am talking about a current copy (or copies) of the book, I would say "This book is written in English." If I want to say that the book was written in English before not, but is possibly no longer written in English, then I would say "This book has been written in English." I would not be talking about a single book or books that I see or have, but the title in general.