i dont have oily skin and i usually use a powder blush but you can use a creme blush if you want.
you want to apply it with a brush that is going to do so lightly such as the MAC Duo Fibere Brush (also known more commonly as the "skunk brush" its not made out of skunk but its because its black and white fibers. lol) this will give you the most bang for your buck with blushes. it will use the least amount of product but still give you the look you want...ie it will last you longer....it gives a look kind of like an airbrush makeup.
just be careful with creme blush at first....you dont wanna over do it...once you get the hang of it it will be second nature...and you can still use a pressed powder over it.
and also if you tend to get oily during the day they also make oil absorbing sheets that are AMAZING!! You just blot them on your face and it takes away all the oil and leaves the makeup. clean and clear makes a simmilar one but they are smaller.
(sorry i am a makeup artist so i tend to leave huge posts to these makeup questions)