So this post is about how I managed to hook up my shiny new (actually there are already the first few spots on the keyboard...) netbook to the inceadible Fonic UMTS flat rate. They offer a USB stick (a Huawai E160 internally) and a SIM card for 90 Euros. There is no further monthly cost and you only pay 2.50 Euro per calender day you use it. That includes the first GB at UMTS speed per day, if you need more it drops down to a GPRS connection.
The fact that you can read this post is proof that I got it to work as I type this in the departure lounge of Schönefeld airport waiting for my flight to Munich.
Basically, there are two pieces of software that are required: usb_modeswitch which turns the stick from a USB storage device to a serial device. I wanted to compile it myself which lead me to learn (I didn't expect that) that the GNU Linux of the Aspire One comes without the C compiler and I had to manually install gcc. Furthermore, this had to be selected from the list of packages since just selecting the "development environment" of the grouped package selection lead to a version conflict that the stupid package manager (I was complaining about before) was unable to resolve. But once gcc is there, compilation is a matter of seconds. I also had to move the config file to /etc and change a few semicolons which are the comment markers to activate the sections that refer to the E160.
So now, to make a connection I turn on the Aspire One and insert the Fonic stick. Then, as root, I run
usb_modeswitch -c /etc/usb_modeswitch.conf -W
The actual connection is made with umtsmon. I have to wait a few seconds after running the usb_modeswith as otherwise the stick will not be detected. In the config the APN has to be set to pinternet.interkom.de and the checkbox noauth as to be ticked while "replace default route" has to be unchecket since the version of pppd that comes with the Aspire One does not understand this option (which apparently was introduced by SuSE and adopted bey Debian). Then you click connect and it should work!
Update: I forgot to mention that because you had to disable the "replace default route" option, the default route (if existent) will not be disabled. Thus you either have to do it by hand (using 'route') or better just make sure you don't have already a network connection running when trying to connect eg. WiFi (and why would you want to connect UMTS if you already had a better newtowrk connection???)