The most commonly used toolkit for Java web services - which works well with Tomcat - is the Apache Axis open source toolkit. There are actually two versions, Axis and Axis2. Axis is mature and Axis2 is evolving.
There is great potential of confusion when speaking of the Axis toolkits because both Axis and Axis2 are simultaneously in use with "version 1.4" the latest for both line. Axis2 is intended to support more of the evolving SOAP, WSDL, and WS-* standards with a faster and more flexible architecture. It even has partial REST support.