Cooking chocolate

[Knipples]

I'd like to make the people in my office (there are 9 including me) a little easter cake this week. We have an abundance of rice crispies in the house, so I thought I could make chocolate crispie cakes with a couple of mini eggs on the top.

Am never sure what chocolate to use for things like this, and how best to melt it. Can someone give me some tips so I can make some nice cakes thankyou please.