Im wondering how to do this...and exactly what they are--i keep seeing people talking about them...but i have no clue....

are they difficult? what do you use them for?

Chocolate transfers are clear sheets of acetate that have colored cocoa butter on them, in patterns. You melt chocolate and pour it on the transfer, then you can wrap a round cake or make panels for a square cake. You let the chocolate set and then peel off the acetate. The pattern stays on the chocolate.
I buy mine at Beryl's:

http://beryls.com/Chocolate_Transfer_Sheets/c10/index.html

If you look in my photos, there are several pictures of cheesecakes I've wrapped with chocolate transfers, and I also did a wedding cake I used them on.

They're pretty easy to use, and sure give a cake a "wow" factor!

Jodie