SP1 of Reporting Services can be downloaded from the following site:
It contains the following new enhancements and fixes:
- Excel rendering extension has been improved and now supports viewing in Excel 97 and 2000.
- PDF rendering extension is more robust and has better performance.
- Chart control provides more control over display styles.
- References to external URLs (images and resources) from within a report are now supported.
- Data caching behavior for report preview is now supported.
- Newline in expressions is now supported.
- The style of the HTML Viewer toolbar can now be modified through a style sheet.
- New URL parameters offer more options for customizing report presentation at run time
- Report Manager proxy persists authentication cookies so that they can be used by custom security extensions.
- Hidden parameters are now supported.
- Temporary snapshots can be compressed as well as stored on the file system.
- Integrated security support for accessing report data sources can be disabled.
The Readme file is a good place to start to get the latest, in-depth info on the above improvements (okay, I know nobody reads the readme, but I'm a doc guy and I have to plug it, and it will seriously be worth your time if you are interested in any of the SP1 enhancements).