If your host platform is Windows then use the Windows Installer/Updater package. For OSX and linux users there is a perl script at http://sourceforge.net/p/devkitpro/perlupdaters/ which will automate most of the instructions here. We would obviously prefer to have a good cross platform installer setup that works the same way for all platforms but making that happen is proving difficult.
The first thing that you need to do is create a folder for the devkitPro toolchains. Start by opening a terminal - on OSX use the apple key + space, then type terminal. This command creates the new folder.
sudo mkdir -p /opt/devkitpro
Once you've done that you can grant world access to the folder so you can extract the archives with normal privileges.
sudo chmod 777 /opt/devkitpro
When we're done the layout for your devkitPro folder should end up like this, each folder links to the appropriate sourceforge package.
Nothing else should be placed inside these folders unless otherwise instructed by the devkitPro toolchain maintainers. On Windows several of these folders are removed and replaced by the update system.
The first package to install is the devkitPPC tarball, obtained from the devkitPPC link shown above. Download the appropriate tarball for your host platform - the files are named as devkitPPC_<revision>-<processor>-<os>.tar.bz2. For OSX we provide universal binaries - devkitARM_<revision>-osx.tar.bz2.
For linux there are two tarballs, devkitPPC_<revision>-i686.tar.bz2 for 32bit systems and devkitPPC_<revision>-x86_64.tar.bz2 for 64bit systems.
Once the file is downloaded then you need to extract it into the devkitpro folder
cd /opt/devkitpro tar -xvjf <file you downloaded>
Obviously replace <file you downloaded> with the name of the file obtained from sourceforge. On OSX you can simply drag & drop the downloaded file into the terminal window to get the file path.
Now you need to obtain the support libraries.
Download the latest binary of libogc then create a new folder and extract the tarball from the terminal window as before. Note: This is the file without "-src-" in the name.
mkdir libogc cd libogc tar -xvjf <libogc tarball>
Again, replace <libogc tarball> with the name of the file obtained from sourceforge. On OSX you can simply drag & drop the downloaded file into the terminal window to get the file path.
Now download libfat-ogc.
tar -xvjf <libfat-ogc tarball>
Now all that remains are the examples archives. Move back to the devkitpro folder and create an examples/wii folder.
cd .. mkdir -p examples/wii
Grab the wii examples archive from sourceforge & extract it here.
tar -xvjf <examples tarball> cd .. mkdir -p examples/gamecube
Grab the gamecube examples archive from sourceforge & extract it here.
tar -xvjf <examples tarball>
Add these variables in your execution environment, for instance, editing the .bashrc file located in your home folder:
export DEVKITPRO=/opt/devkitpro export DEVKITPPC=$DEVKITPRO/devkitPPC