Yep, the RC for Silverlight 5 now supports Tasks. You can do your own parallel processing in Silverlight 5 now.
Oh, and here are some of the other features:
- P/Invoke (Native function calls)
- 64 Bit
- Vector Printing
- Remote Control and Media Command Support (I have no idea what this is.. time to do some reading)
- DataContextChanged Event
- In-Browser Trusted Applications
- PivotViewer Control
- Power Awareness
All in all, some cool features seem to be coming..