Went to an Adobe Seminar last week and notice a nice feature in Flash CS3 - Full Screen Video. In Flash CS3, when your use the FLV playback component, you can choose the type of skin and some of them had the option to enable full screen video.
Beside that, you also need to change the HTML Publish Setting Template to Flash Only - Allow Full Screen.
Below are some sample on creating a simple full screen video. Script can be implemented to change the background color when in full screen mode, etc.
1) Create a New Flash File (ActionScript 3.0)
2) Select Window > Components to drag out the Components panel.
3) Expand the Video selection in the Components panel and drag the FLVPlayback to the stage.
4) Select the Parameters tab and set the FLVPlayback component size to your video size.
5) Select the skin and choose a skin that allow Full Screen. i.e. SkinOverPlaySeekFullscreen.swf
6) Proceed to select the source of your video (in flv format).
7) Finally, go to File > Publish Settings.. and select the HTML tab. Under the Template dropdown selection, change the selection from Flash Only to Flash Only - Allow Full Screen.