There is errata to 1st edition French rules. It was once available in web, but I don't know where it can be acquired now. You can find it in Web Grognards site in French.
There is no official erratas available to English 2nd Edition rules.

Europa Universalis mailing list, which is used to collect this FAQ, is found from:
        www.yahoogroups.com/group/EU-list.
Europa Universalis resources can be found in:
        EU-list web pages by John Quarto-von Tivadar. Supplements discussion on the list.
        Ville Virrankoski's EU site Maintainer of the FAQ.
        Vincent Chretien's French 1st edition site. Really good!
        Maxim Tanone's web site
        Alvaro Prada's EU pages
        Guillaume Petraud has been working with Java based EU tools and new maps
        Stefan Huszics has information from both board and computer EU
        Stéphane Thueux's web site
        Web Grognards has also some links to EU resources.
Europa Universalis promotial pages:
        <Addresses for reviews etc. gaming groups, stores, magazines...>

There is one extension available, which contains >200 new counters, which include leaders, missions, missionaries, forts etc.
There has been rumours about second extension, but no-one has yet seen it.

Update 2000/10/08: AWE announced that the second extension will be released in French mid or late October 2000 and then they will translate it to English.

AWE sold computerization rights to the Swedish software company Target Games, aka Paradox Entertainment, which has been working to transform this game to computer. They chose to make some very drastic changes to the game system, like changing it to pseudo real-time to speed the network play. Promotional pages are in www.europa-universalis.com.

AWE announced Oct 3rd 2000 that they are working on the 3rd edition of EU. It will be released first in French and after it is OK, they'll translate it to English using native English speaker to do translation.