I actualy got steam running under Linux,
not with wine though. its not made for running games, wineX is.
just install wineX from cvs.
I did a search on this very forum and found a script that downloads, configures and installs the thing. its called GetCVSWineX
you can download a binary or rpm also, its better and more stable but they charge you for it.
i had to install the tahoma font, but other than that it worked.
I hope you have a fast pc though, performance still doesnt come close to running it on windows.