Apache Solr 1.4 has been released and is now available for public download!

http://www.apache.org/dyn/closer.cgi/lucene/solr/

Solr is the popular, blazing fast open source enterprise search
platform from the Apache Lucene project.  Its major features include
powerful full-text search, hit highlighting, faceted search, dynamic
clustering, database integration, and rich document (e.g., Word, PDF)
handling.  Solr is highly scalable, providing distributed search and
index replication, and it powers the search and navigation features of
many of the world's largest internet sites.

Solr is written in Java and runs as a standalone full-text search server
within a servlet container such as Tomcat.  Solr uses the Lucene Java
search library at its core for full-text indexing and search, and has
REST-like HTTP/XML and JSON APIs that make it easy to use from virtually
any programming language.  Solr's powerful external configuration allows it to
be tailored to almost any type of application without Java coding, and
it has an extensive plugin architecture when more advanced
customization is required.

New Solr 1.4 features include:

- Major performance enhancements in indexing, searching, and faceting
- Revamped all-Java index replication that's simple to configure and
  can replicate config files
- Greatly improved database integration via the DataImportHandler
- Rich document processing (Word, PDF, HTML) via Apache Tika
- Dynamic search results clustering via Carrot2
- Multi-select faceting (support for multiple items in a single
  category to be selected)
- Many powerful query enhancements, including ranges over arbitrary
  functions, and nested queries of different syntaxes
- Many other plugins including Terms for auto-suggest, Statistics,
  TermVectors, Deduplication