According to a short news blurb on the official Steam site, Human Head and 3D Realms' Prey will be available on Steam as of tomorrow, November 30. It will run $49.95. Unlike most non-Valve games distributed through the service, Prey will allow Steam activation by way of a product key from a previously purchased copy of the game, either retail or downloaded. Prey is not the first product from publisher 2K Games to come to Steam, though its arrival on the service is slightly surprising given the less than favorable attitude towards Valve's service that has been espoused by 3D Realms, most recently from company head Scott Miller.