Here is my implementation for a chamber of commerce:
http://cohase.org/bizdirectory2/index.phpAs you can see, this is fully integrated into the site. It involves some relatively minor changes to the php, mostly in terms of adding IF clauses along with a few new fields in the database.
Some changes/enhancements to the basic version include:
- Completely done in css with no tables
- The left-hand pane of categories is always displayed
- Only categories containing active listings are displayed in the left-hand pane (This eliminates what I consider a major annoyance for users - clicking on a category only to discover that there are no listings in that category. It also shortens the category list)
- Only sub-categories containing active listings are displayed in the main pane
- Email addresses are clickable links
- Advanced search has been removed (We don't have enough listings to need this)
- The admin section now shows listings alphabetically when showing all listings
- Added fields for Mailing Address, Contact Person Name
- Allowed for Custom Google Map where the 911 address doesn't show proper location
- Added ability to print a membership (re)application form already filled out
Note that I am not a php programmer. Being able to do this kind of an integration involves knowing css, html, being able to guess at most of the php, and leaving alone the parts I don't understand. It was made
much easier by the fact that BizDirectory is modularly written

I could not have done this with a lesser or more convoluted script.