We are looking to upgrade a site to from Drupal 6 to Drupal 7 that uses the Advertisement module. There is an alternative module to the Advertisement module for D7?
Just released is the SimpleAds module for Drupal 7. This module provides a way to feature advertisements on a Drupal website. It displays graphical ads in configurable blocks. It records and reports useful statistics. It is easy to configure and does not depend on other contrib modules.
You can try OpenX.
Show ads from a OpenX (formerly OpenAds) server. OpenX is a open source online program that will allow you to catalog and display advertisers, just like Google, Yahoo or Microsoft.