I would like you to try out Apache Scout, the first open source implementation of the Java API for XML Registries (JAXR). Why am I preaching it? I wrote it.
JAXR is a specification that is mandated by J2EE 1.4 specification. I integrated Apache Scout (JAXR implementation) and Apache jUDDI (UDDI v2.0 compliant) into JBoss, since v4.0.2
So if you are in need of a UDDI registry and a standard way of accessing it, please try out JBoss v4.0.2 (or later).
JAXR in JBoss