Hi I always see that most of the white cakes have a really white fondant but even dough i ve made diferent types of fondant they all still look a little less white. I wonder if there is a trick to a whiter fondant that i havent really found. Thank you for your answers.

I make Michelle Foster's Fondant in the recipe section here - it comes out white. Are you looking for a whiter white than that?

Wilton's makes a product called "icing color white-white." You can add some to your fondant and that will help.

well to me it does not look that white to me when i am handling it so i guess it could be me or could it be that the whites in tv they buy it from providers. Well i guess i am going to have to get used to it. Thank you

Yes, you need to get the "white" color. It's wilton brand which should be in the same location in the store as where you buy the normal gel colors. It's more of a liquid than the gel colors and it works great! I add it to my homemade MMF when I put the marshmallows with the shortening in the begining and it's instantly white white!!
Here is a cake that I used it with:

http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1522103

I've used the Wilton whitener to brighten up some really off white icing and it worked great. Did it with these cupcakes:

http://cakecentral.com/modules.php?name=gallery&file=displayimage&pid=1455110