First go to "System>Preferences>Network Connection".
Then click on "Mobile Broadband" tab and click on the add button.
Now we're half way there. To make it work you'll have to download this package:
sudo apt-get install udev-extras
Then you'll create a file for the modem by typing:
gksu gedit /etc/udev/rules.d/15-huawei-e1550.rules
Then paste this code in the gedit window:
RUN+="/lib/udev/modem-modeswitch --vendor 0x12d1 --product 0x1446 --type option-zerocd"
cAll you'll need next is to plug and enjoy.
The last step was optained from here.