Microsoft launched "Games for Windows Marketplace," which's streamlined to provide an easy way for PC gamers to discover, buy, and download their favorite games.
Anyone can browse the marketplace, but to buy and download all you need to do is sign in with your Windows Live ID. GWM integrates with Xbox LIVE so if someone signs in with same Live ID they use for Xbox LIVE, GWM will display their Gamerscore and Xbox LIVE avatar at the top right.
The frontpage of GWM makes it very easy to dive right in -- allowing you to sort by featured games that change all the time, new releases, top downloads, LIVE-enabled games (my favorite), or all games. This's also where you'll find "Deal of the Week" and "Daily Deal" as we're continuing the tradition of offering hot deals for game titles through the marketplace.
Today's Daily Deal is Grand Theft Auto IV at 40% making the game only $11.99.
More Info: Games for Windows Marketplace