The WotLK Information Wiki formerly had detailed information on the spells and abilities of the new hero class, the Death Knight, as well as new 51-point talents for most classes. It also hosted and updated a copy of the latest build of the Alpha client, and showed previews of numerous models in the expansion such as speculated vanity pets and armor sets. None of this information is currently available, although the site's message states that they are "having a little trouble" and "hopefully will be back shortly". The current refuge of Alpha-hungry players are in an IRC channel called #wotlkwiki in irc.mmoforge.org, where the header cryptically (or not-so-cryptically) states that "THE MEN IN SUITS, THEY TOOK THE WIKI ON VACATION TODAY. Might return tonight."
If the Alpha wiki team succeeds in conforming (or going around) the rules laid by the intellectual property firm, it might return to serve up information sometime soon. We'll keep a close eye on these developments; whatever happens, we've learned that it's tough to keep a good secret from getting out.