It has come to our attention that it is possible to preload the Counter-Strike: Source early off Steam.

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To do so run this: "X:Program FilesValveSteamSteam.exe" -applaunch 260

Where X is the drive on which Steam is installed.

Neither Condition Zero or an ATI voucher are required to preload. However, it is locked and not currently playable.

Source: Nikush.com