gooday, I see in some of the post people talks about "supporting" the cake when theres more then one level, with what do support and how?

Each layer should have cardboard, foamboard or something under it. Then, you can put down into the bottom two cakes, dowels, large straws or plastic tubes that will "hold up" the next upper level of cake. (the plastic tubes can be bought in the cake decorating section of the store) Just make sure what ever you put down in to the cake is ok to touch the cake, metal would not be. Most people also put a dowel all the way through the layers of cake to the bottom for extra support.
Is this what you are asking about???

Here is a tutorial that should help http://cakecentral.com/articles/107/building-the-cake-combination-pillar-stacked-construction

Thanx so much exatly what i was looking for!

And here's another idea.
http://cakecentral.com/cake-decorating-ftopict-603925.html