How do I setup a Huawei E220 USB wireless modem in Ubuntu linux?

I have one of those USB wireless modems, a Huawei E220, which I can use to access the internet from many Australian cities using the three network. The modem works fine in Windows but I had many problems to make it work in Ubuntu. I finally found some useful information on the web, and the process is not as hard as I thought could be. Here's a summary of how to do it. But first of all, an explanation of how the modem works.

After plugging in the USB modem, two USB devices are created in /dev/TTYusb0 and /dev/ttyUSB1. The first one, /dev/ttyUSB0, is the actual modem. The computer sees the modem as a dial-up modem. So to use it, the computer needs to use the modem and "call" a special phone number via the modem. This can be done with the program wvdial.

To configure wvdial, edit the file /etc/wvdial.conf so that it looks like this (you need to edit with sudo and have administrator permissions):

[Dialer Defaults]
Init1 = ATZ
Init2 = ATQ0 V1 E1 S0=0 &C1 &D2 +FCLASS=0
Modem Type = Analog Modem
ISDN = 0
Modem = /dev/ttyUSB0
Phone = *99#
Username =
Password =
Baud = 460800
New PPPD = yes

That's it! You can type whatever you want as a username and password. Now plug the modem, wait for a few minutes until the device /dev/ttyUSB0 exists, and run the following command:

wvdial Defaults

For some reason that I don't understand, the first time I try this the connection always drops, so I need to unplug the modem, plug it again, wait a few minutes and then type wvdial Defaults again. Then it works.