Fortunately the Huawei E1550 seems to be quite a popular modem therefore searching for instructions on how to set it up on Ubuntu Lucid Lynx led me to some handy instructions here - http://franklinchua.wordpress.com/2010/05/03/huawei-e1550-on-ubuntu-10-04-lucid-lynx/ (note: i used gedit instead of vi. so feel free to replace that bit if you want to.)
Once you've got your system to recognise the modem (and not only the memory), you will need to set up the your service provider and APN details via network connections. The details for getting connected on to Zain Zambia's 3G network are:
Service Provider: Zain
APN: internet
Plug those details in and you should get online with ease after that.
Update (1.11.10): When I used the method above I had a problem with using other usb devices to my laptop. I've found out that you can also get the modem to run by simply running the following command. If you used the instructions on the previous page, delete the file you created. :
$ sudo apt-get install usb-modeswitch
$ sudo usb-modeswitch
Other usb devices should now be able to connect with while you have your 3G dongle on.
