Collections provide an option to select columns to be display within the table view of collection.
We are extending most content-types with two fields using archetypes.
In the control panel -> collections ( typically /portal_atct/atct_manageTopicIndex) you can define every metadata you need. Collections depends on portal_catalog metadata and indexes, so you've to add your custom fields there. Use GenericSetup in your module profile to tell ZCatalog to create the new indexes, or create them by hand. In the former case, beware that reinstalling the module could wipe out the new created indexes ( http://maurits.vanrees.org/weblog/archive/2009/12/catalog ).