There is a README file in /usr/share/doc/packages/virtualbox-ose/README.SUSE that has info about running VirtualBox as normal user.

You can use YaST2 to add your user to vboxusers or run this command as root:

usermod -A vboxusers username

Replace 'username' with your user and logout/login. You should find the emulator listed in the kickoff menu under system > Emulator. It started as normal user for me this way.