Do the following to setup GDM to auto login with a specific account. Also setup the GNOME keyring to not prompt you for a password when connecting to a saved wireless network. First, edit the /etc/gdm/custom.conf file and add the following options: NOTE: Below is the older method that works with Fedora 12 and under:
[daemon] TimedLoginEnable=true TimedLogin=username TimedLoginDelay=5
NOTE: This method works with Fedora 13 and up:
[daemon] AutomaticLoginEnable=true AutomaticLogin=username
The TimedLogin/AutomaticLogin option should be set the username you want to auto login as. The TimedLoginDelay should be set to the number of seconds to wait before auto logging in. The GNOME keyring stores saved wireless passwords. If you set the keyring to the same password as your login then it does not prompt everytime you login to open the keyring. However once you enable auto login it will then prompt you every time you login. Do the following to disable that: Go to "Applications->Accessories->Passwords and Encrypted Keys" from withing GNOME. Right-click on "Passwords: login" and select "Change password". Then change the password to a blank password. This will disable the prompting for a password to open the keyring. NOTE: you may need to install Seahorse in newer versions of Fedora to do this.
UPDATE: With Fedora 32 you can now just go to Settings -> Users and select the user. Then turn on "Automatic Login".