Please bear in mind the reason we haven't updated isn't because we don't want to (the ops aren't just sat around a big red Update to 1.2! button toying with us). As you may be aware, servers like the addicts rely on plugins to deliver our unique experience, furthermore, these plugins rely on a system called
Bukkit to function. Due to the significant amount of changes that have been made for Minecraft 1.2 (for example, the higher worlds, new region format, new NPCs etc. etc.) Bukkit probably requires quite an extensive re-write to allow it to work with the updated version of Minecraft (which is what the hard-working folks over at Bukkit are in the process of doing now). At the time of posting, Bukkit don't yet have a stable release candidate for 1.2, let alone a recommended build which effectively means that servers which rely on plugins to deliver their experience cannot yet update.
As you may have seen in another section of the forums, Bukkit are now part of Mojang which should help them get their recommended build out quicker than they've previously been able to, however, this is by no means the end of the story. As soon as the Bukkit update is released, plugin developers must also update their plugins to work on the latest version of Bukkit. Due to the fact that there's so many new features in the game, most of the plugins will require at least some changes to function on 1.2 (sadly we can't simply use old versions). As I'm sure you can imagine, most of these plugins are pretty crucial to our experience (in areas such as protecting builds for example) and therefore updating without them is out of the question.
As I previously mentioned, there is a significant bright side in Bukkit's co-operation with Mojang which is hopefully going to get them up to date quicker than they've previously been able to. In addition to this, plugin devs are a resilient bunch and should hopefully be able to get their respective plugins working with 1.2 before too long and rest assured, as soon as we're able to the ops will get us up to date.
Remember, Minecraft Addicts has been running since September 2010 which means people like MrJangles are among the most experienced ops in the business; so for the time being please be patient and rest assured that things are being taken care of, also if you require instructions on how to rollback your client to 1.1 simply click the link in the green bar at the top of the page.
tl;dr Please be patient, the ops are on the task and we'll update as soon as we can, in the meantime, feel free to rollback and enjoy the server as normal!