I installed tomcat 4 several years ago, with a variant approach to the article on developer.apple.com. Was kind of a pain then. I can't remember how I did it.
I like on windows how you can use the installer to run a net service. Then make batch files "net start tomcat" and "net stop tomcat" and put those on the taskbar, then add respective start/stop icons w/them. click the icon to start or stop tomcat. Simple and easy to set up and use,
I reread the article on Developer.apple.com but want tomcat visible in the finder, not hidden. I can't seem to get it right. I checked the permissions and the ownership but it doesn't work. tomcat 5 does not appear to start, tomcat 6 fails with "permission denied" in Terminal.
I searched for, but did not find an installer for os x. It is really taking too much time to get this done; should be a 15 min job (that's how long it takes on Windows) but I've spent over half a day and can't figure it out.
Just like for you, Tomcat 4 was the first one I installed on OS X, and while it was a pain to get it right the first time, the later installations of newer versions went quite well. I went by this article which provides all the details.
You don't have to run Tomcat under its own user account, but to mirror a proper production environment, I do. Just remember that everything in the TOMCAT_HOME directory needs to be owned and have the proper permissions accordingly.