As Steam for Linux is now available (with a sale to celebrate that) you might want to run Steam natively on your Linux OS rather than wrapped in wine. Even though Valve only offers Ubuntu packages for download, the Steam client can also be installed on other Linux distros. While many of them don’t include Steam in its official repositories due to licensing concerns (a notable exception is Fuduntu), there are other ways to get Steam through 3rd party repositories.
For Fedora 18 there is one repository available here. They provide packages for Fedora 17 and Fedora 18. All you need to do is grab steam.repo from there and copy it to /etc/yum.repos.d:
$ cat steam.repo
name=Steam RPM packages (and dependencies) for Fedora
After having copied the repository run yum to install Steam:
$ sudo yum install steam
If you run into dependencies issues make sure you have the RPMfusion repositories installed (both rpmfusion-free and rpmfusion-nonfree).
This Steam package, while not official, it is perfectly legit as the package builder asked for Valve’s approval before releasing it. After the installation, when you start Steam for the first time, it will auto-update itself so you’ll be running the latest version.