(This post would probably be better placed in the Developer forums).
1. Are you planning to insert that module into the main moodle? When (if you can make a guess)?
Yes. Maybe in a couple of weeks. It is definitely going to be the most complicated module, so it will need lots of testing.
2. If you have a beta-version may I download a copy of the quiz module?
You can see beta code in CVS (read the developer docs). It might be working by the end of the week.
3. Moodle would perfectly integrate with Php-nuke (or Php-Proxima), why don't you think to build moodle as a php-nuke module?
Why don't you think to build PHP Nuke as a Moodle module? I'm not a fan of PHP Nuke and personally I can't really see the point in integrating them. Don't let that stop YOU doing it however!
4. I'm building the Italian language block... I'll send it to you when ready.
Italian has been started already ... check CVS for the latest version by Davide Suraci.
5. I'd like to select if the students can or cannot post replies in the forums and the group of people (students, teachers, admin...) that can post topics.
Already done in CVS .. coming in 1.0.6.