I have oily skin too! Before I put my make-up on, I put on some toner (I like Origins). I also use a face wash specifically for acne (Neutragena Stress Control). There are also these oil absorbing tissures that soak up the oil and don't mess up your make-up (these are the kind that I use) : http://www.thebodyshop-usa.com/bodyshop/browse/product_detail.jsp?categoryId=cat30030&productId=prod150041
Good luck! =]