Just to confirm the new EU cap on data roaming, which will save quite a few surprise bills when using Smartphones in Europe. But the best advice is to switch off data roaming altogether when travelling abroad and especially when outside of Europe:-
There are a number of changes that will be happening regarding data roaming from the 1st July 2010. These changes have been introduced by the EU and therefore affect all networks and all users sending and receiving data whilst travelling in a European country.
In summary, these changes are: