Well Wilton has come up with a quick and ingenious way of sealing those crumbs in so they can't get in your icing. It's called Spray 'N' Seal and the name says it all. Here's how it works:
Your cake needs to be cooled, filled and ready to ice. Then you'll simply shake up your can of Spray 'N' Seal and spray a nice, healthy layer over your entire cake. Let it sit in the fridge for a few mins so it can set. Then you're ready to ice and decorate!
Here's WHY it works:
The product is basically solid shortening in a can so once you spray it on and let it set it's like a thin shield (or force field) around your cake, keeping the crumbs in and preventing your icing from pulling up. It has no smell or taste so no one but you will know it's there. It's also made from the same ingredients as most icings.
The only flaws I see is that you won't be able to use it with any kind of cream based icing. The oils will break down your icing and you'll end up with a runny mess. Also, remember that this is a spray OIL so you should have a cover and/or project board to protect any surfaces. If you're an airbrush artist like me then you probably have these on hand anyway.
Pros over cons, this product is another great Wilton invention and something EVERY baker (beginner or not) should have on hand! You can find video on how to use Wilton's Spray 'N' Seal at... http://www.youtube.com/watch?feature=player_embedded&v=wSS1IFgv3lo