pi@rpi-cseye:~ $ sudo apt-get upgrade E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable) E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?
As suggested by MadAntrax, reboot your Pi and then run the command again. This is a somewhat common hiccup, either a previous apt-get command stalled and hasn't released the directory, or another process is running an update command.
sudo reboot or
sudo shutdown -r now
sudo apt-get update
Have you tried updating your RPI? If not:
sudo apt-get update && sudo apt-get upgrade