"LingSIG" is the short name of the Special Interest Group called "TEI for Linguists". The resources for this project include:
The way to join in is by creating an SF account and messaging Piotr. Please note that, due to the apparently very limited amount of extra time in our group, and to certain limitations of Subversion that make it difficult to maintain a virtual mirror of the TEI trunk across separate repositories, we have opened a dedicated LingSIG branch within the main TEI repository. Still, our versioning system can be used for quick jobs that you might want to distribute among the group or just safely store.