Patch 4.2 is out in the US today and will be hitting EU servers tomorrow.
Professions don’t see much of an update, so none of the leveling guides will be impacted by this patch. Some professions will see new recipes, but as I understand it, these will require raid related reputation in order to purchase them. Also, all of the existing iLevel 339 PvP recipes have been updated to iLevel 358.
Some thing that looks really cool in this patch is the Dungeon Journal. This provides more information about dungeons, such as bosses and their abilities. Here’s hoping that having this information in game will improve the quality of some PUGs.
For details of all the new content and features, check out the following Blizzard article – Rage of the Firelands