The holder of an IMC rating can fly IFR in uncontroled airspace and controlled upto class D. You can file an IFR flight plan or request an IFR clearance on route if you know what you want and ensure you are not directed through/via an airway or airspace above class D.
When I initially trained for the IMC rating I was told minimums of 1800 meters viz for departure and a cloud base not less than 700 feet? I think, Minimum for an approach procedure I was told was 700 feet for a non precision and 500 feet for a precison approach.
However another examinar told me that this was not in the air navigation order so was only advisory and you could effectivley use lower minimums if required, (he also said don't be a fool and ensure you are in current pracise, aircraft is properly equiped etc.) but I am unsure where the definitve answers can be found, hopefully someone can put a link up!