Lately when I make my buttercream it seems to taste gritty. Can anyone tell me how I can get it to be creamy.

Any help appreciated.

Nanacin

I'm assuming this is a powdered sugar-based recipe?  If so, did you change the brand of powdered sugar?  I only use Domino 10x, and I sift it before I add it to the butter.  To me, powdered sugar-based buttercreams always have a slight "bite" to them, because the powdered sugar doesn't fully dissolve into the fat.
 

Just like AnnieCahill mentioned, try a different brand of powdered sugar.  Generic brands tend to be grittier than name brands.

Besides trying a different brand, mix your icing longer!  Most recipes - especially if from Wilton - tell you to mix *just until incorporated* but that is NOT enough.  If you mix it on low for at least 5 or even 10 minutes you will find a much creamier product. 

Next thing to try is to increase the fat (butter, margarine or shortening).  Sometimes all it needs is another Tablespoon or two to make a big difference :)