"We're going to have one package, The Orange Box, available on the PC (US$49.99) as well as the 360 and PS3 (US$59.99)," said Valve's Doug Lombardi to IGN PC. "Those who purchase the PC version of The Orange Box will get three separate Steam product codes: One for the three new games, one for HL2, and one for Episode One. This way a PC Orange Box owner can give away their Half-Life 2 or Episode One unused Steam product codes if they don't need a copy of those games."
It is unknown whether this development will impact the Steam pricing models for the upcoming games. Shacknews has contacted Valve for more information, but had not yet received a response at the time of this printing.