Last night Sling Media released updated the SlingPlayer for Windows 2.0 Public Beta with the release of the second beta build. The new build, .457, replaces the first beta build, .447, and can be downloaded from the Sling Media website. (Also for Canada.) Users who had previously installed Public Beta 1 will be prompted to auto-update SlingPlayer to the new beta build.
Disclaimer: I work for Sling Media as a Beta Manager.