Here's the changelog: http://jakarta.apache.org/tomcat/tomcat-5.0-doc/changelog.html#Tomcat%205.0.24%20(remm)
I created a new ebuild for Tomcat 5.0.25. It's an "almost clean-room" implementation that removes alot of the external configurations and gives you a very clean tomcat install. It's under Bug 51466(http://bugs.gentoo.org/show_bug.cgi?id=51466)
Tomcat 5.0.25 is in portage but masked, feel free to test it out and let me know how it works for you. Note that tomcat uses a new layout scheme...