Fully automatic build

Just open terminal and execute this commands:

wget https://github.com/xvitaly/steamrpm/raw/master/genrpm.sh && chmod +x genrpm.sh && ./genrpm.sh

Then go to Step 7.

Step 1

Download original package for Ubuntu:

cd ~
wget http://media.steampowered.com/client/installer/steam.deb

Step 2

Unpack Ubuntu package by using ar tool:

cd ~
ar vx steam.deb

You will get three files: debian-binary, control.tar.gz and data.tar.gz. We need only data.tar.gz. All others can be deleted.

Step 3

Install RPMBuild. On Fedora/CentOS/RHEL:

sudo yum -y install rpm-build

On openSUSE:

sudo zypper install rpmbuild

Step 4

Rename and copy data.tar.gz to rpmbuild working directory:

cd ~
mkdir -p ~/rpmbuild/SOURCES/
cp -f data.tar.gz ~/rpmbuild/SOURCES/steam.tar.gz

Step 5

Download spec file for rpmbuild:

cd ~
wget https://github.com/xvitaly/steamrpm/raw/master/steam.spec

Step 6

Run rpmbuild:

cd ~
rpmbuild -bb --clean steam.spec

You will get Steam RPM Package for GNU/Linux in ~/rpmbuild/RPMS/i686/ (on 32-bit systems) or in ~/rpmbuild/RPMS/x86_64/ (on 64-bit).

Step 7

Install package. On Fedora/CentOS/RHEL:

sudo yum -y install ~/rpmbuild/RPMS/`uname -m`/steam*

On openSUSE:

sudo zypper install ~/rpmbuild/RPMS/`uname -m`/steam*.rpm