GeoServer is an open source, standards-based server of geospatial information, connecting spatial databases and files to the variety of clients that make up the 'geospatial web', and allowing user contributed editing through standard web-based interfaces. GeoServer can be downloaded at geoserver.org
Improvements for this release include an upgrade to GeoTools 2.2.x, and some performance tuning on the toolkit, with users reporting at least a 60-70% speed increase against PostGIS. There are also great user contributed fixes to create PDF maps from WMS and to adjust headers to allow caching, which can optimize GeoServer for tiling web mapping clients like Google Maps or KML/KMZ output from the open standard WMS protocol, which is compatible with Google's network link. Also funded was a basic SLD creation wizard, so that map styles can be created through the web administration GUI.
With the latest additions GeoServer becomes an ideal server for Google Earth, especially for connecting with existing spatial databases. GeoServer supports PostGIS, ArcSDE, MySQL, Oracle Spatial, DB2, and Shapefiles and recent improvements with GeoTools 2.2.x pass the majority of the spatial processing back to the database. There is also a KMScore optimization, which has GeoServer render the features as a raster to be used as a Ground Overlay, for situations when there are too many features for Google Earth to efficiently portray. GeoServer is able to handle millions of rows in a geospatial database, and will perform quite nicely as long as the map is styled efficiently with the Styled Layer Descriptors (SLD) specification from the OGC. GeoServer remains 'standard by default', so all layers configured for Google Earth will also be available as standard WMS and WFS. GeoServer's transactional capabilities also allow a community of users to update spatial data, and have it available in a variety of formats.
GeoServer is an Open Source server that connects your information to the geospatial web. Its focus is ease of use and support for standards, including serving as WFS 1.0 Reference Implementation (and soon to be 1.1 as well). The goal is to serve as 'glue' for the geospatial web, connecting from legacy databases and formats to many diverse clients. GeoServer includes easy to use installers, web administration tools, and demos to get you going quickly. GeoServer's homepage is geoserver.org, and more information on features can be found on the features page. The latest release is found here. The GeoServer Project is completely open source, in license and development process, built by a diverse community of contributors, whom you are encouraged to join. GeoServer is built on GeoTools, an incubating project of the new Open Source GeoSpatial Foundation .