Parameterized Parameter Prompts
One new SSRS 2008 feature that international users will undoubtedly appreciate is parameterized parameter prompts.
Previously, the parameter prompts were static. In SSRS 2008, you will notice the familiar function symbol (fx) next to the parameter prompt which means that the prompts can be expression-based. This allows the report author to change the parameter prompt caption at runtime. For example, you can retrieve the localized version of the parameter prompt from an external resource assembly based on the user language.
UPDATE 03/27/2009 This feature didn’t make it to the release version of SSRS 2008. SSRS 2008 doesn’t support expression-based parameter prompts. The feature has been slated to a future release.