Meresco is both an OAI Data Provider and a Service Provider. SourceForge is only used to host the source control (subversion). Sources: http://sources.meresco.org/ Binaries: http://repository.cq2.org/ Mail: http://groups.google.com/group/meresco
Nucular Archiving System for creating full text indices for fielded data. Python API, web, and command line interfaces. Fast. Very light weight. Concurrent read/writes with no possible locking issues. No server process. Proximity. Facets. Funny name.
A configurable knowledge management framework. It works out of the box, but it's meant mainly as a framework to build complex information retrieval and analysis systems. The 3 major components: Crawler, Analyzer and Indexer can also be used separately.
Xapian is a Search Engine Library, written in C++ with bindings for Perl, Python, PHP, Java, Tcl, C# and Ruby. Xapian allows you to easily add advanced indexing and search facilities to your applications. See www.xapian.org for more information.