I read through different sites and some mention turning off IIS and setting up Apache as the web server. Other sites describe setting up IIS to work with Tomcat. I am not sure if I need to do either as the Head First Servlets and JSP book does not detail this step. I would appreciate some advice on which path to choose (intalling apache to work with tomcat or setting up iis to work with tomcat) and details on how to set up tomcat.
Neither Apache nor IIS are needed to work with Tomcat. If you're chiefly interested in Tomcat's ability to run Java web-apps, then I'd advise not to install Apache - it just complicates things. You can leave IIS running, but you need to ensure that it uses a different port than Tomcat.
If IIS is set up on port 8080, you can have Tomcat use a different one. Look through the %TOMCAT_HOME%/conf/server.xml file for mentions or "8080", and change them appropriately.