There was some misunderstanding regarding the similarity computation needed for the project. The project description has now been changed to state that you need to do both the raw term frequency based similarity and the tf-idf based similarity. You can now also attempt an extra credit part where you evaluate the effectiveness of tf-idf scheme.
Here is a direct link to the project page. http://rakaposhi.eas.asu.edu/cse494/s10-project.html
Thanks and Regards,