You can grab the bits from here. If you have V3 CTP1 installed, please uninstall it first or you can get your machine into a bad state.
So far my favorite two features new to this drop are both in the Integrated Scripting Editor (ISE). The first is the “most recently opened files list” on the File menu and second is the switch to a two pane ISE (combines the output and command panes into one). Oh yeah, there isn’t much in the help system until you run Update-Help from an elevated prompt.