can anyone suggest the best way to deal with a class that's shared between a client and WCF?

I'm just beginning to test things out. I've taken the console class as-is and added it to a project that includes a WCF project. and I'm trying to replace the existing GetCustomer call with the RESTful GetCustomer call that I've put in my WCF service. the problem is that I get a conflict between the two (but identical) classes (I had to add the "Customer" class to my WCF Visual Studio project). I assume this is a simple problem for those who understand the principles of object-oriented programming. I'm only now trying to do things the right way ;-)

I've actually just solved the compilation problem by simply taking out the class definitions in the client (almost too obvious), but the only curious thing is that I had to change the CustomerView Render method, to change Count from a property to a method by simply adding parentheses.