I have seen many cakes with buttercream or royal icing transfers and just wondering how to do it? Thanks!

Here is a tutorial.
http://cakecentral.com/articles/73/how-to-create-a-frozen-buttercream-transfer

I have watchedd this tutorial and I have a question. It may be a dumb one but, here goes! When you are filling in the design do you pipe it with a star tip or just fill in with a round tip? I used the round before and had trouble getting a smooth finish on the front.

I've always used a round tip. Smaller for the tight areas, larger for the bigger. I thin my icing a bit so it more or less "flows" into the area I need filled. HTH.

Thanks! I'll try it!