The Forza Motorsport 4 Demo will be available for download by XBOX LIVE GOLD members on Oct 3 and Silver members on Oct 10. http://forzamotorsport.net/en-us/wir_9-23/
For all the latest and greatest details on Forza Motorsport 4 be sure to check out their website: http://forzamotorsport.net/en-us/Default.aspx
And be sure to also check out the Forza Motorsport forums for all latests discussions, insights, tunes, paint and any other help you may need: http://forums.forzamotorsport.net/Forums/
The Forza Motorsport community is a close knit group of people that are always will you to assist anyone from beginner to expert. I look forward to seeing you all in the game.