Change Tomcat port to 80 with Apache?

You can use mod_proxy for passing the data over to tomcat.

you could use something in the lines of:

ProxyPass /myservlet http://localhost:8080/myservlet
ProxyPassReverse /myservlet http://localhost:8080/myservlet

That will proxy the data to the tomcat instance and rewrite replies so that they match the given path. I would recommend using something like nginx for plain proxying, but if you already need apache for something, it can be done with it too.