Cool as it might be, having a SideShow supplemental display on the outside of your laptop isn't the most essential thing. Yes, it's handy to be able to check your calendar or address book without booting Windows up fully, but most power-users (i.e. the people who would be most likely to use SideShow) will already have that information on their smartphone. Far more practical is Interlink's SideLink remote control for Windows Vista Media Center; it has a SideShow display from which you can browse listings and recorded shows, set programmes to record, even preview recordings should you enjoy watching them on a tiny screen.
Wireless communication with the remote is likely to be Bluetooth given the company's existing product range, and no release date has been given (perhaps considering that the official Vista release is yet to happen).