You really have two problems here, and I think you should attempt to address them separately.
- Problem 1 is getting the data from the Server
- Problem 2 is parsing the data you get from the Server.
Both these problems have been covered extensively on this and other forums previously, so I suggest that you search here and elsewhere. Here are a few links from SO:
blackberry HttpConnection.GET
Parse XML file on BlackBerry
In addition, I recommend you review the documentation provided on the official BB site:
http://developer.blackberry.com/bbos/java/
including the following:
http://developer.blackberry.com/bbos/java/documentation/intro_networking_1984362_11.html
As you will see, the BB offers a number of methods of doing communication, in your case I would recommend the ConnectionFactory API:
http://developer.blackberry.com/bbos/java/documentation/network_api_1984363_11.html
And here is something on parsing XML:
http://supportforums.blackberry.com/t5/Java-Development/Use-the-XML-Parser/ta-p/445210
This should be enough to get you going. Please come back with specific questions if you have issues with any of this.