In order to view a chat session, you need to :
1) Download SkypeRevealer for windows (Download), or Adobe Air version (Download), if you are on Linux or Mac, Please install Adobe Air Runtime before using this application (Here Adobe Air).
2) Enter a valid Skype uername then click check
3) If you entered a valid username you will see somthing like this.
4) Choose the contact from the list in order to view the entire conversation