pg_senna is a project to allow Senna fulltext search engine (http://dev.razil.jp/project/senna/) to work under postgresql, for fast and accurate fulltext searches (especially in Japanese)
The pg_sennaproject is a PostgreSQL Community project that is a part of the pgFoundry.
The pgFoundry page for the project is at http://pgfoundry.org/projects/pgsenna, where you can find downloads, documentation, bug reports, mailing lists, and a whole lot more.
