There is internet on the train in Sweden. On my way to Oslo through Göteborg coming from Linköping. (The train is called the X2000. I guess that was cool back when they made it up.) We’re not exactly saving time by going through Göteborg, but the alternative was getting on the train at eight which is not acceptable after any decent Christmas party. The reason we were in the Linköping office was to have a meeting about meetings, very meta, though reasonably productive. And it’s also nice to hang out with the other people from Opera working on standards and politics involved in standards, as well as meeting the people from the Swedish office, of course.
The price for wireless on the train is 89 SEK for two hours, which is about 10 EUR. Not too bad although apparently it is free in some other countries. In the Netherlands there is no such thing as wireless on the train. Just on the train stations which is pretty crappy. I guess the real solution here is for mobile network providers to modernize their industry and start providing global fixed rate access to the internet through handheld devices.
For the last couple of month's I've been using mobile internet on a daily basis in the train in the Netherlands, between Amsterdam and The Hague, and it works great! I use the Huawei E220 USB stick, that has a built-in HSDPA/UMTS modem, paying 30 euros a month for unlimited internet access at 384 Kbit/s.
I take the train to work every couple days (40 km through the Chicago, US area). Unfortunately there's no internet on the train there, though it could be useful. Occasionally some of the stations will show up in the wireless networks, but that's fairly useless.
There is a train line between Amersfoort and Ede-Wageningen in the Netherlands which is called 'De Valleilijn' (The Valley Line). According to posters in the train you can use free wireless internet while on board. However, this train line is not run by the NS (the largest Dutch railroad company) but by Connexxion (a smaller one).
I've tried the Wifi on the X2000's and to be honest it sucked.
I get a more reliable connection using my (work payed) 3G connection, which is pretty impressive considering I travel through some fairly uninhabited parts in the Stockholm region.
According to the NS website they are (in combination with KPN) expanding their in-train services to include wireless Internet access. They did a trial on one line last year.
(BTW I think that what Robbert was referring to was normal phone modem access which has nothing to do with a service from NS.)