I have recently started to use fondant and gumpaste to decorate both wedding and party cakes. I am having trouble getting a smooth and even finish. My iced cakes start out nice and even and smooth but when I cover them with the fondant you can see a bulge where the layers have icing. I have tried to roll it thicker and I even once applied two thin layers of fondant instead of one thick one. Nothing seems to work. What am I doing wrong? Thanks

Here is an article that might help..
http://cakecentral.com/articles/68/solution-for-cake-bulging-between-layers

I also found that I really have to have a smooth finish on my coat underneath the fondant. I like to use a bit more icing than a basic crumb coat to enhance the taste, so I use a hot knife to smooth (dipped in hot water) then let dry/crust a bit. Works well for me...

It sounds like your layers might be bulging. This happens when your cake settles after you put the fondant on it and icing and filling smoosh out the sides. Try letting your cake sit for a few hours or overnight before you put on the fondant.

I also suggest you try using ganache. I've never had a buldge since I started using it.

I second the suggestion of trying ganache, I love it and it sets up so nice and firm that there's no chance of bulging.