where to start w/plugin to allow link submissions?

Been reading the manual as much as I can … pouring through source code, yet I’m still not sure where to start.
I essentially want to create a form that would allow registered users to select a category and then submit a weblog via the /wp-admin/link-add.php form without compromising security.
Basically, I want to convert blogs4God.com to WordPress or Drupal … if I could give reg’d users an input form to list their sites, I think I’d like the light-weight aspects of WP.