iBook publication in another countries

Hello,

I have a question about the territories for iBooks publication and I would be very happy if someone could answer my question.

I work in company in Czech Republic and we would like to publish our book (which is already published in print version in stores throughout Czech Republic) to as many countries as possible.

Our main goal is to publish it in English speaking countries - USA, UK, Australia etc.

Is there any problem with that, or we just choose in which countries we would like to publish the book during the publication process in iTunes Producer? Is there any things that needs to be settled first? Are there any fees?

Thanks a lot for your insights!