In the web.xml of your war, have the following entry:

<ejb-ref>
 <ejb-ref-name>GiveAnyNameByWhichYouWouldLikeToReferTheBeanInYourWebApp</ejb-ref-name>
 <ejb-ref-type>session</ejb-ref-type>
 <home>packageName.ClassNameOfTheHomeObjectOfTheBeanYouWantToRefer</home>
 <remote>packageName.ClassNameOfTheRemoteObjectOfTheBeanYouWantToRefer</remote>
 </ejb-ref>

In the jboss-web.xml of your war, have the following entry:

<ejb-ref>
 <ejb-ref-name>GiveAnyNameByWhichYouWouldLikeToReferTheBeanInYourWebApp(This should be same as the one given in the web.xml above)</ejb-ref-name>
 <jndi-name>TheJndiNametoWhichTheBeanIsBound(Example:somecontext/somejndiName)YouWillFindThisJndiNameInTheJboss.xmlOfTheEJB</jndi-name>
 </ejb-ref>

For more info, have a look at the dtds of web.xml :
http://java.sun.com/dtd/web-app_2_3.dtd

and jboss-web.xml:
http://www.jboss.org/j2ee/dtd


In your code, do the lookup as:

Context ic = new InitialContext();
 Object ejbHome = ic.lookup("java:comp/env/TheNameThatYouHadGivenInTheEJB-REF-NAMETagOfJbossWeb.xmlAbove");

Here's an example:

web.xml:

<ejb-ref>
 <ejb-ref-name>MyTestBean</ejb-ref-name>
 <ejb-ref-type>session</ejb-ref-type>
 <home>com.test.ejb.MyBeanHome</home>
 <remote>com.test.ejb.MyBeanRemote</remote>
 </ejb-ref>

jboss-web.xml:

 <ejb-ref>
 <ejb-ref-name>MyTestBean</ejb-ref-name>
 <jndi-name>myejb/test/MyTestBean</jndi-name>
 </ejb-ref>

Lookup code:

Context ic = new InitialContext();
 Object ejbHome = ic.lookup("java:comp/env/MyTestBean");