Attached to this post is the version 2.0 beta of the Post Indexer plugin. This plugin has had quite a big update to bring in the WP 3+ terms and category taxonomies.
It should work and function correctly with the other WPMUDEV global post plugins and widgets *except for* the current version of the Global Tags plugin (the beta version of which will be available in another sticky post pretty soon).
This plugin adds two new tables to your database, so you should check that these have been created if you come across any initial issues (also, if you are running multi-db, then make sure these are in your global tables list):
Any other issues, please post below.