How can you create string templates (placeholders) for your application in C#.net?

I am looking for a way to establish error message templates and have parameters become part of the message. Just concatenating a string on the fly is not a very clean approach to this problem and I'm sure there is a better way to address this. The idea is that the messages can be easily changed and if there are place holders for the parameters then you wouldn't have to change the code to have your message display properly.