From 1 July 2012, using mobile internet to access maps, videos, photos, social networks and email will be much cheaper while travelling in other EU member states. A new EU regulation means that, for the first time, there will be a maximum charge for "data roaming" - downloading data from the internet when using a mobile connection.

Overall, the improved EU roaming regulation will deliver consumers savings of 75% across a range of mobile roaming services, compared to 2007 prices. By 2014, as prices are cut further, the maximum cost of downloading data will be just 20 cents per Megabyte, plus VAT. Operators are free to offer cheaper rates.
Also, as of 1 July 2012, to help avoid "data bill shocks", people travelling outside the EU will get a warning text message, email or pop-up window when they are nearing €50 of data downloads, or their pre-agreed level. This extends the alert system currently in place within the EU.
The measures are the first in a series of progressively reducing price caps, eventually leading to a new system that will introduce choice, competition and new great roaming deals into the market by allowing consumers to choose a separate roaming contract before they travel or a provider at their destination, similar to the way they choose a Wi-Fi network.

More information: http://ec.europa.eu/information_society/activities/roaming/index_en.htm