ArcGIS 9.3 is expected to be available in the third quarter of 2008. ArcGIS Desktop 9.3 is supported on Windows Vista, Windows XP, Windows 2003, and Windows 2000.

At 9.3, ArcGIS Server support for KML has been greatly enhanced. At 9.3, when you publish a map service, the KML service option is automatically checked. At 9.2, you had to manually check the KML option.

Improvements to KML support in ArcGIS Server 9.3 include

* Automatic availability of KML through REST
* Use of KML Regions to display cached map services
* Availability of KML for image services
* Availability of KML footprints through REST
* Ability to select a label field
* Ability to turn labels off
* Ability to select lines and polygons
* Ability to view the legend for a service (This legend comes from the ArcMap Page Layout view.)

In ArcGIS Server Manager, under Applications, you can administer KML network links.

ArcGIS Server 9.3 map services can return the results of geoprocessing, geocoding, and query operations as KML. These services can be used in applications and can also be used directly by analysts typing in REST URLs. This is a good way to allow applications and users to selectively retrieve information from online geodatabases in KML format.

All map and image services expose a KML network link through REST. REST is a way of exposing information about your services through a series of navigable URLs. At 9.3, you will be able to discover the URL to the network link using what we are tentatively calling the ArcGIS Services Explorer, which is an application designed to help you navigate the REST endpoints on your server. If you’re participating in the beta program, you can see examples of the Services Explorer. Essentially, it is like a metadata report for each of your services with links showing how that map service will appear in a variety of applications including ArcGIS Explorer, Google Earth, Google Maps, Microsoft Virtual Earth, and ArcGIS Desktop. The URL points to a .kmz file that you can add to Google Earth or any other client that supports KML network links.

Support for PostgreSQL (Open Source DBMS)

* Enterprise geodatabases can be implemented on PostgreSQL with full support of the geodatabase data model.
* Vector geometry is stored in the ESRI spatial type.
* PostGIS Open Source spatial type is supported.

Read more at http://esri.com/software/arcgis/about/whats-coming.html