> So, I'm thinking I should just hook_init, and based on the > http request, alter $base_url if needed, and do a > variable_set that I later retrieve in the theme to alter (or > not) the background-image used as the top banner. Is this the > best approach?
Whatever you do, if you think you need to alter $base_url, then you are most likely approaching your task at hand wrongly. Drupal usually sets up $base_url correctly and you should not alter that value. If you need conditional settings per site, then you should look into Drupal's multi-site support. sun
