how do i create a site that allows users to create "organizations? I'm creating a site where users should be able to create organizations(groups) that other users should be able to join....a list of these orgs should be accessible by all users of the site on an "orgs" page.....whats the best way to do this? thank you very much!
The module to do this with in Drupal would be Organic Groups https://drupal.org/project/og. It's not a trivial module though. Here's the official documentation: https://drupal.org/node/1114858.

There are some online courses available from for example Lullabot: http://drupalize.me/series/organic-groups-drupal-7
and Brian Lewis: http://modulesunraveled.com/organic-groups-7x-2x.