Konami's PC port of Saw, which went out earlier this month for Xbox 360 and PS3, will hit Steam later this month. It will also be available on IGN Direct2Drive.
Big Download originally reported that it would be a Steam download exclusive, noting that Konami did something similar last year when it put out Silent Hill: Homecoming.
Correction: However, Konami contacted Kotaku to say that Saw will be available via Steam and Direct2Drive later this month.
PC Version of Saw to be Exclusive to Steam [Big Download via VG247]