This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
Using JNDI will only work for Java clients, as you point out. But is also uses some non-standard ports which you may not want to open up to the world. Web Services require only port 80 (and/or 443), which are usually open already.