I'm making my own wedding cake...a simple 3 tiers with ribbon as accents...is there a trick to applying the ribbons to the cakes? Is there a certain type of ribbon to look for so that the oils from the buttercream don't react with it?

You will just have to experiment with what ribbon will work best. Perhaps something that is coated or metallic. Some ribbon will aborb the oils uniformly so that it may be slightly darker but not unattractive. (Try florist ribbon for this) I incorporate a twist-tie into my bows leaving the two ends long. I push these in to the cake to help attach the bow. Keep it small or be sure that some of the bow is resting on the cake top or board.

If you are just wrapping the ribbon around the cake, you need to pipe a line of icing immediately before applying it to the cake. Sometimes it is easier to put this on the ribbon rather than trying to get it straight on the cake. Decide what is the back of the cake before you start and be sure that the ends meet at the back! Sounds silly, but it is easy to forget this in the heat of the moment.

I made the mistake...ONCE, of using a wire edged ribbon on a cake. The ribbon has a "memory" from being on the spool and is very hard to shape to your cake. I have also used the floral ribbon, as suggested above, and had no problems with it...it was a black ribbon though, so I'm not sure if the oils from the icing affected it or not, if so no one was able to tell!

Not my idea, but I got it here.

I was told that you can use something like waxed paper behind the ribbon if you are using it on Buttercream. I did that for the cake that I have in my gallery. What I did was lay the ribbon in stips on the tape to the size of the layer + a little more then take double sided tape lay it across the ribbon then use wax paper strips to that. That way the waxed paper absorbs the buttercream (not the ribbon). I think if you;re are using fondant, then just ribbon should be okay or just to be safe line it with Wax paper too.

Found this thread that may be of help: http://www.cakecentral.com/cake-decorating-ftopict-12293-ribbon.html

I have used satin ribbon in the past with buttercream and fondant covered cakes and had no problems with grease stains or spotting.

I covered the back of my ribbon with contact paper so the oils from the frosting wouldn't seep through and stain my ribbon. I've also heard you can put your ribbon on waxed paper (back side of the ribbon on waxed side of the paper) and iron it and the heat will transfer the wax to your ribbon and it will act as a barrier.