This is a really cool article about getting Apache SOAP up and running on a Tomcat Java server. I've tried the Apache SOAP library before (last year actually) and it seemed a bit kludgy, but it seems that they've done some work to get it working a lot smoother now. (Or at least there's an intelligent article about getting a basic system working.)
I'm wondering if the code will work well outside Tomcat - like on the Resin server my hosting provider uses (http://www.cwihosting.com )... This is important because I really don't think that Tomcat is ready for primetime just yet - even with the new Catalina engine. If it runs nicely on OrionServer (which is also the base of Oracle's 9i Application server too) that would be great. Though I haven't given Orion any money yet, they have THE best JSP/J2EE server there is.
Also, the Apache folks have another project called Axis which is supposedly the "next generation" version of the SOAP stuff. The idea is that the original code was based off IBM's work and it's not really the most efficient in the world, so they rewrote everything from scratch as Axis. This seems like the library to use, even if it's only in Alpha state right now because it uses the latest and greatest Sun stuff (like JAXR) and is written to be a lot more scalable. Time will tell... (I don't actually get why Apache always has two versions of projects... Tomcat 3.1 and 4 for instance and the two different versions of the RegEx stuff for Java.)