Russia has agreed to let the EU monitor the flow of gas through the Ukraine, though negotiations over how the monitors will function are still on-going.
The inability of Ukraine to pay its bills and suggestions that Ukraine has been taking gas bound for the EU has provoked this move. Sarkozy has also questioned Ukraine's dependability as a partner.
While this in no way solves the core problem of Ukraine's gas bills, it does mark a step in the EU trying to ensure that the member states will get the gas they pay for, and that Russia has no excuse to turn off the tap to those who pay their bills. Of course, this is also in Russia's interests, as it makes the question of Russia's dependability as a gas supplier less pressing - which is important at a time when Russia needs all the business it can get.