JBossDeveloper

I changed my web.xml to simple :
<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.2//EN" "http://java.sun.com/j2ee/dtds/web-app_2_2.dtd">
<web-app>
<resource-ref>
The default DS
<res-ref-name>jdbc/SQLServerPool</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<res-auth>Container</res-auth>
</resource-ref>
</web-app>

Then there is no mistake happened,I use this in my servlet test:

Properties h = new Properties();
...
InitialContext initCtx = new InitialContext(h);
out.println("got context");
javax.sql.DataSource ds = null;
ds = (javax.sql.DataSource) ctx.lookup("java:comp/env/jdbc/SQLServerPool");
if(ds==null)out.println("ds is null");
....

it just stop for "ds is null".
I use tomcat 4.0 and Jboss 2.4 and had done all the things as metioned by up you kind friends.
So what's the problem?
Thanks
shink

tclouser,
As you said my jboss-web.xml is as follow:
<?xml version="1.0" encoding="UTF-8"?>
<jboss-web>
<resource-ref>
<res-ref-name>jdbc/SQLServerPool</res-ref-name>
<res-type>javax.sql.DataSource</res-type>
<jndi-name>java:/SQLServerPool</jndi-name>
</resource-ref>
</jboss-web>

I don't deploy any EJB in Jboss,is that reason I can't use datasoure in servlet?