Hi, I just wrote a long reply, then deleted it again, because I'm not 100% sure on it.
If you have a control panel like Plesk or Cpanel, you might run into problems. If you have blank server with just the operating system to start with (which you can get from us), you should be able to just follow the documentation and install it. I'm not really sure how it would work out with Jboss and an existing control panel. It might not work.
I'd say that it would be replacing Resin rather than working next to it. Probably replacing standard Apache too, which Cpanel and Plesk wouldn't cope with.
My advice would be to stick with Resin if you are using Cpanel and Tomcat if you are using Plesk. Plesk can use Tomcat, it's an option in the control panel. Cpanel and Resin have been set up by us to work together, so that's fine too. If you are looking to install JBoss, it's fine, we support it, you can put anything on the dedicated server, but you might be creating a big headache for yourself. This sounds like a cop-out, but really, you need to balance up what extra features you are going to get with the pain of installing it, if it isn't really going to work properly with the control panel you have installed.
We can install it for you for $75 an hour which is always an option there if you like. Last time I installed Tomcat, I just doubleclicked the install file and it worked