Thanks for the input. Greatly appreciated. I also had missed the updating of web.xml and jboss-web.xml and didn't have the datasoure name correctly specified in the Java code.
Here's what it looked like when I finally got it to work.
Java souce code
private static final String DATA_SOURCE_NAME = "java:jboss/datasources/sybaseDS";
...
Context ctx = new InitialContext();
System.out.println( ctx );
DataSource dbSource = (DataSource)ctx.lookup( DATA_SOURCE_NAME );
ctx.close();
webapp/web/WEB-INF/web.xml
<resource-ref>
<res-ref-name>jdbc/sybaseDS</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
<res-sharing-scope>Shareable</res-sharing-scope>
</resource-ref>
webapp/web/WEB-INF/jboss-web.xml
<jboss-web>
<resource-ref>
<res-ref-name>jdbc/sybaseDS</res-ref-name>
<jndi-name>java:jboss/datasources/sybaseDS</jndi-name>
</resource-ref>
</jboss-web>
jboss-as-7.1.1.Final\modules\com\sybaseDS\sybase\main\module.xml
<module xmlns="urn:jboss:module:1.1" name="com.sybaseDS.sybase">
<resources>
<resource-root path="jconn4.jar"/>
<!-- Insert resources here -->
</resources>
<dependencies>
<module name="javax.api"/>
</dependencies>
</module>
jboss-as-7.1.1.Final\standalone\configuration\standalone.xml
<datasources>
<datasource jndi-name="java:jboss/datasources/sybaseDS"
pool-name="sybaseDS" enabled="true">
<connection-url>jdbc:sybase:Tds:10.250.5.27:5000</connection-url>
<driver-class>com.sybase.jdbc4.jdbc.SybDriver</driver-class>
<driver>sybaseDriver</driver>
<security>
<user-name>sa</user-name>
<password>angels</password>
</security>
</datasource>
<drivers>
<driver name="sybaseDriver" module="com.sybaseDS.sybase"/>
</drivers>
</datasources>