In the Release records, there is a Schedule tab that shows your milestones and tasks along with a '% Done" column. However, it only show the percent complete on the milestone as 0 or 100. You can manually enter the percent done on the Milestone record, but it seems like it should calculate that on it's own. For example, if there are 4 tasks in a Milestone, each task completed should automatically increment the % complete by 25.
Seems like this could happen in a calculation rule. Does anyone know how to do that? It would have to dynamically count the number of 'live' child tasks (ignoring any that are cancelled or rejected), evaluate the status of each, then calculate the percentage of 'Status = Completed' from the total.