Unable to mount Galaxy S2 on Debian Squeeze laptop as storage device
This comment helped me, though I also had to create a udev rule https://android.stackexchange.com/a/5067/11156, the udev rule is given below, please note that kumar is my username on my box.

SUBSYSTEMS=="usb", ATTRS{idVendor}=="04e8",
ATTRS{idProduct}=="6640", MODE="0660", OWNER="kumar",
GROUP="plugdev", SYMLINK+="android%n"
SUBSYSTEM=="usb", SYSFS{idVendor}=="04e8", MODE="0666"