Do I use buttercream or fondant to achieve this effect? And, how thick should I make it? It looks to just be cut into with a knife/spatula, so if I could just figure out what to use, I don't think it should be too difficult. Thank you for your help!

I would say it was buttercream or a whipped cream type frosting, just because of the peaks at the top edge. Scored with a knife or spatula, yes.

That looks like buttercream to me. I think they just used a skewer to drag the pattern.

great! Thank you both so much for the input!! I'm going to practice this weekend (the wedding isn't until the 14th), but wanted some other input to help me along. Haven't ever done this type before.

wow, that is pretty how they did the frosting!

White chocolate ganache:

http://www.flickr.com/photos/charlysbakery/3207094913/

Oh, thank you!!! I tried to find this, but the girl who gave me the pic didn't have the link, she just put it on a cd.

Woww
I love it ! I have a feeling that its more whipped cream than butter cream,mgood luck and waiting for yours !

Really! I would have sworn it was SMBC. Anyway, it's a beautiful effect.

For future reference, you can drag any photo into the regular google search box and it will scour the web for that photo. Then you can maybe find the original source with more info, like the pp was able to get