I have recently installed Organic Groups on Drupal 6.15.
After reading thru OG's docs and scanning the admin pages I cannot for the life of me figure out where you go on Drupal admin to see a list of any groups created for group management.
I do see an 'Organic Groups' page on Drupal but that is for configuration and doesn't show me a listing of groups.
Logically I'd assume it would be found under Content Management where stuff like Forums is also listed but it isn't there.
*UPDATE*
Ok, I'm using OG with the domain access module and had it set to enforce rules on administrators. Groups are specific to each subdomain so I wasn't seeing all the groups on the groups link with the enforced rule setting. I had to visit the subdomain to see the group.
So I'm guessing OG doesn't provide an admin page to list & manage groups.
