Thankyou for your replie ondrejv,
im new to c# could u post a sample code which shows how to make a web part, essentialy how to merge two datasets? and is there any confugration i need to do on my visual studio?

Anyway, i tried using query data soruce to select both tables, something like "SELECT * FROM CMS_news (found this table name from query tab in cms_news document type) AND View_Cms_Tree_Joined (found this table name from some rss document type) ORDERBY Date DESC;"

im pretty sure view_cms_tree_joined isnt the right table for getting rss data. is there any way to find tablename created by xmldatasource to store data?

cheers