"Hey. For all those who will be installing skyrim from retail copies, sometimes steam will actually install the game from the servers (download) and not from your disc. This is a workaround. Works for steamworks games only, and does not work until the official launch time.
Using Steam launch options to install retail games from disc
Log in to Steam and click on Library.
Right-click on the game, select Delete local content, and confirm.
Insert the first disc into your computer.
Close Steam (Steam > Exit).
Press Windows Key + R to open Run
In the Run window type:
"C:\Program Files\Steam\Steam.exe" -install E:
Replace E: with the CD/DVD drive you are installing from if is not correct.
Replace C:\Program Files\Steam if your Steam installation is not in the default location.
Press OK. Steam will launch and ask you to sign in if you do not have your password saved. Your installation should continue from the disc."
http://forums.bethsoft.com/index.php?/topic/1255286-pc-installing-skyrim-from-disk-not-steam/