@Lucy
Yesterday's changes were proposed by the EU-commission back in September 2008 and passed the last instance in the legislative procedure, the EU parliament, in April 2009. So that was expected for months now.
By the way the prices mentioned in the article, you posted, are without VAT and the cap of data tariffs does not apply for consumer prices, but for wholesale price (what operators charge each other for roaming customers using data).

How do these changes affect international SIM providers?

Are the MNVO's registered and operating in EU countries required to offer the Euro-tariff?

How about operators based in an EU-country but hosting MNVO's registered and operating outside of the EU?

What about the other way around (I think eKit & Mobal are examples)?