I run IIS and Tomcat on the same machine.
Have you remembered to start Tomcat? Have you got the Tomcat icon in the status bar to confirm that it has started OK? If no, then try to start Tomcat manually: C:\jakarta-tomcat-5.0.12\bin\startup.bat
Once you have verified that Tomcat is started then type the following into your browser:
You should be at the startup screen.