Android is moving away from USB Mass Storage. You will no longer be able to plug in a USB cable and have your Android show up as a USB disk. There are some good technical reasons for this, but it is a pain if you want to copy some files to your phone. The new system - MTP - isn't automagically detected in Ubuntu. This is something which is likely to be fixed in later versions of Ubuntu - but for now you'll have to hack around it.

The crazy cats at omgUbuntu have a tutorial which I have adapted for the Samasung Galaxy S (running ICS from teamhacksung).

First, install the MTP tools.

sudo apt-get install mtp-tools mtpfs

Connect the phone to the computer using USB.

To check that MTP is installed and working, run the command

mtp-detect

You should see a spool of text as MTP detects the phone.

To create the rules which allow Ubuntu to detect the phone, create a new rule file like so:

sudo nano /etc/udev/rules.d/51-android.rules

Add in this line of text

SUBSYSTEM=="usb", ATTR{idVendor}=="04e8", ATTR{idProduct}=="6860", MODE="0666"

If you're using a different device, run this command to get the correct idVendor and idProduct:

mtp-detect | grep idVendor
mtp-detect | grep idProduct

We'll need to restart udev so it can pick up the new rule.

sudo service udev restart

Then create a directory in your filesystem which you can use to access your phone.

sudo mkdir /media/GalaxyS
sudo chmod a+rwx /media/GalaxyS

Now we need to add ourselves to fuse.

sudo adduser YOURUSERNAME fuse
sudo nano /etc/fuse.conf

The last line probably reads

#user_allow_other

Remove the "#" so you're left with:

user_allow_other

Save the file.

We're going to create two commands "android-connect" and "android-disconnect". When run, these will allow you to connect to your phone, then safely disconnect.

echo "alias android-connect="mtpfs -o allow_other /media/GalaxyS"" >> ~/.bashrc
echo "alias android-disconnect="fusermount -u /media/GalaxyS"" >> ~/.bashrc
source ~/.bashrc

Restart the computer. Make sure the phone is connected via USB. Open a terminal and run

android-connect

Open your file manager and go to "/media/GalaxyS"

Once you're done, disconnect the device by running

android-disconnect