As far as I can see there is no parent class of the ad box that identifies it as being on the main page like other module so i've had to use some script. not ideal as it'll do that old Ning favourite of 'now you see it now you don't' when the script runs LAST!
Anyway, try this, assuming you've got the ad box above header. replace http://www.yourmainpageurl.com':
<!-- Remove Top Ad Box from Homepage -->
if (window.location == 'http://www.yourmainpageurl.com')
Put in Custom Code
Thanks a million and I'll try that. I understand what you mean and will see what the load times are.
Hopefully Ning is listening and will give us options for restricting ad boxes on certain parts of the site (I know that many want it to not appear on profile pages - based on the threads of this forum).