BTW, only because I read this term so often here: Whats a "data plan"? My interpretation so far was it was some kind of additional contract you need to get online with your mobile carrier. Is it? Or is it the mobile internet-access you sign up for (with extra hardware to be plugged into your laptop) independent of any mobile voice contract you might have?

I'm confused because here, when you own a phone thats capable of any kind of data mode, you just go online with it. No need for an extra contract/"data plan"/whatever. (There are special rates for heavy users, as there are for people who do a lot of voice calls or primarily international calls, whatever, but thats an extra...)