Hello dear Gdansk team.
3) Finally (but this question is irrelevant if 2) is taken care of)
can the default language for the website be English, and not Polish?
Wikimania is an international conference, and navigating in Polish is
well... sorry, but very difficult :)
This isn't a solution, but I recently discovered it (via Pharos, thanks) and have found it very helpful. For Gmail users, in Gmail labs (little green lab beaker icon in the upper right-hand corner) there is a tool called "Message translation".
If you enable it, it puts in a google translate button right in your email for messages it detects are in a language that is not your default language. Polish->English (and vice versa) is one of the options. I know the translations are not very good -- the grammar is pretty awful :) -- but it's better than nothing!
Anyway, while I agree with Del that the default language of the website and conference should be English (at least the public facing parts), please don't let language stop you from posting on this list or other wikimania planning lists to plan the conference. I think everyone on Wikimania-planning-l and this list is willing to see messages in Polish (or any language) :) And I would really like to see more international participation in planning, which can only happen if the conversation is held in public places.