Drupal 7 was released 13 months ago, and while Drupalcon sites (like Denver and Munich) are built on Drupal 7, none of the permanent Drupal.org sites are on Drupal 7 yet (or started to being ported to Drupal 7). This is usually due to (a) huge custom built modules or setups used that are hard to migrate (b) ongoing improvements to introduce better user functionality. With localize.drupal.org the situation is a bit more interesting. As I wrote in my last news post in October, Dashamir Hoxha mostly updated the huge base module for the site to Drupal 7 and Organic groups has a Drupal 7 version too, so the two biggest base modules are available. There are some interesting challenges however. The drupal.org theme (bluecheese) is not yet ported to Drupal 7 (help at http://drupal.org/node/1438716), the Organic Groups User Roles module functionality is integrated in Groups for Drupal 7 but there is no upgrade path and we'd like to switch to simpler solutions from the Messaging and Notifications monolith.
The update to Drupal 7 would be great to lead by example for other sites on drupal.org as well as keep improvements to the Localization Server module suite to one active branch. With the Drupal 7 port there and the Drupal 6 version used actively on the site, feature requests and bugfixes come in for Drupal 6 and there is a lot of extra work to port them to both versions at once.
Finally, I don't personally have time to head the effort but I can help provide guidance. Sebastien Corbin signed up to help do test upgrades and would very welcome any of your help. Want to work on updating the Drupal.org theme to Drupal 7? Figure ou an upgrade path for Organic Groups User roles to Drupal 7 Groups configuration? Help migrate Messaging and Notifications signups to a simpler framework? There are lots of opportunities to help out there. If you are interested see Sebastien's issue at http://drupal.org/node/1424984 and signal your interest there!