Download the November CTP here

Overview:

SQL Server 2008 Improvement Pillars 

Express Edition Available: download here

[quote]Note: You can also try a CTP version of SQL Server 2008 Express Edition. This free, fully functional edition of SQL Server 2008 is ideal for learning and running desktop and small server database applications. SQL Server 2008 Express supports 1 CPU, 1 GB of RAM and databases that are up to 4GB in size. This software also automatically expires after 180 days.[/quote]

Visual Studio 2005 Support for SQL Server 2008, Community Technology Preview

What's new:

Backup Compression
Configuration Servers
Change Tracking
FILESTREAM Storage
Hot Add CPU
Plan Guide Enhancements
Query Processing on Partitioned Objects
Partition Switching on Partitioned Tables and Indexes
Resource Governor
Extensible Key Management
Transparent Data Encryption
Server Administration - Enhancements of DMF
Spatial Data Storage, Methods, and Indexing
SQL Server Management Studio Enhancements
- Transact-SQL Query Editor IntelliSense
- Transact-SQL Error List Window
- query multiple servers at the same time by opening query windows from registered server groups and the option to combine query results combined into a single results pane
- configure the number of rows that are returned when you are opening tables.
-prevent the table designer from re-creating tables when you are implementing design changes.
Lock Escalation Option for the ALTER TABLE statement

Aggregation Design Improvements
Cube Design Improvements

Creation of Holdout Test Sets
Filtering on Model Cases
Cross-Validation of Multiple Mining Models
Drillthrough to Structure Cases and Structure Columns
Aliasing Mining Model Columns

Enhanced Performance and Caching for the Lookup Transformation
Enhanced Data Type Handling in the SQL Server Import and Export Wizard
New ADO.NET Components
New Data Profiling Task and Data Profile Viewer (Data Profiling)

New Conversation Priorities
New Diagnostic Utility - the ssbdiagnose utility
New System Monitor Object - the Broker Transmission Object performance object
New Service Broker Tutorials